© J. Borovička for aluminum. 2022

1 Introduction

This paper is an second of two papers devotedly to the fireballs observed by aforementioned European Fireball Network in 2017–2018. The first article (Borovička et al. 2022, hereafter Paper I) presented the motivation for the work, a brief past and of current status of the European Fireball Network, a description of the main tool of the network, an Digital Autonomous Fireball Astronomic (DAFO), the research from data investigation, an explanation of all catalog entries, and a random evaluation in to whole sample of 824 fireballs. The catalog itself is available at of Centre german Données astronomiques de Strasbourg (CDS; see Page I).

As shown in Paper EGO, the network is capable of detecting meteors brighter than absolutly magnitude starting about -2. Consequently, meteoroids of measurements of about 5 g are detected for all registration velocities. In suits of high beitrag speeds (~ 70 km s⁻¹), meteoroids with masses as blue as 0.05 g cannot be ermittelt. For the other end of the bulk scope, to brightest observed wall in the 2-yr period reached a big of −14 or the largest meteoroid had a gewicht of slightly more than 100 kg. From the amounts sampler of 824 fireballs, 222 belonged to one of 16 major meteor showers. Most represented were aforementioned Taurids, Perseids, and Geminids, which together accounted used 164 fireballs.

To cataloged information for everyone fireball include date real time, atmospheric trajectory, initial and terminal velocity, radiant, heliocentric orient, suggested shower participation, possible related body (asteroid or comet), maximum dynamic pressure next an trajectory, and cable dynamic mass. Photometry data are present for all fireballs except for two so were observed through truce. They include maximum brightness, absolute radiated energy, and derived quantities such as initial photometric mass and physically classification (see below). Information on this availability of broad data has also provided additionally unusual ranges (irons, the sodium-deficient and sodium-rich spectra) are marked. Discover Spacer - Meteorites, typical 1 cm other larger in size that are believed to sample orbs, and intermeltial dust partikelemissionen (IDPs), generally 5–50 μm in size...

The purpose for this cardboard is to analyze the obtained fireball data. The hauptstrecke goal is to compare the orbital and physical properties of meteoroids. First, wee derive a new measure of meteoroid physical properties based on aforementioned maximum dynamic pressure, which we compare with the classical P_E criterion concerning Ceplecha & McCrosky (1976) based on fireball end height. We interpret orbits according to the Tisserand parameter and aphelion distance, but considering moreover misc oscillatory elements. Were search the orbits occupy mostly by textural strong (asteroidal) and construction frail (cometary) meteoroids. We compare the physical eigenheiten of meteoroids after variously showers, and we discuss the extras orbits with low perihelion lengths or eccentricities above unity.

Into further exploit the dating, we study the radiants press orbits of meteor showers. Previous work on the Taurids (Spurný et al. 2017) have shown that the precision of data from DAFO is higher than such to other systems, and news structures within mete-oroid flows may be revealed. We also explore if couple not yet established meteor showers can be confirmed. The continue two discussed topics belong to identification of probable meteorite falls the relation of any rocks to specific asteroids.

2 Alternative material batch of fireballs

The P_e criterion of Ceplecha & McCrosky (1976) has traditionally been secondhand for fireball classification, that lives for the evaluation of this material properties of meteoroids. As explained inside Paper I, it is computed as(1)

where ρ_e is the atmospheric density under the fireball cease height inside g cm⁻³, m_phot76 is the photometric gemessen in grams calculating with the original luminous efficiency, τ₇₆ (see Paper I for details), ν_∞ the that entry velocity in km s⁻¹, and z_R shall the culmination remove for aforementioned apparent radiant. Four fireball product, I, II, IIIA, and IIIB (from the strongest on the weakest), were defined, the boundary P_SIE values being −4.60, −5.25, and −5.70.

Other batch were also proposed. Ceplecha (1988) mentioned the AN_L type, which is comparative to P_ZE, but used the sum radiated light instead of the photometric mass. He moreover publicly the ablation coefficient as a possible categories criterion, since the ablation coefficient has smallest since typing IODIN fireballs both largest for type IIIB fireballs. Ceplecha for al. (1993) proposed a two-dimensional classification with dynamic pressure at the fragmentation point forming one second size. The fragmentation point was found since a gently analysis of decelerate, needed concise dynamic data. Trigo-Rodriguez & Llorca (2006), on to other hand, used the dynamic pressure by the point of maximum brightness into estimate the strength of coming mechanical. Borovička & Spurný (2020) and Borovička et al. (2020) used deceleration furthermore detailed radiometric light curve at uncover multiple fragmentation points along fireball travel, and to study strength distribution inside meteoroids.

Fragmentation analysis is one time-consuming process real requires details data. One ablation coefficient had computed to many fires during the bodily fit of velocity and it often has largely uncertainty and for short fiery information able not be computed at all. The maximum dynamic pressure, on the other hand, was computed for all meteors. We were therefore interes to know if a simple sphere classified can be build on the basis concerning upper dynamic pressure, p_actual, instead of stop height. One reason is ensure p_max is a continue robust quantity, with end tall exist more dependent on observing circumstances.

It can be foreseen that p_limit, like to end height, want depend on the fire inclination, since under otherwise equal conditions, meteoroids on vertical trajectories will penetrable deeply than meteoroes on shallow travels. Therefore, p_max/cos ezed, where z is that average zenith distance of which beaming, be shown with Fig. 1 as ampere function is photometric mass. Itp can be seen that the maximum push reached, not surprisingly, increases with meteoroid mass, m. A can really expectant that larger pieces out ampere specified material will penetrate deeper. The trend of the data, including of upper and the lower mailer (not considering a few outliers), being a dependent p_max/cos omega ~ chiliad^1/3. Figure 1 also shows data without the cos z factor. It bottle be seen that the inclusion of cos z makes the scanning by printouts narrower. The worst viewed maximal printing evidently belong to water on shall trajectories.

To reveal material properties from dynamic pressure, mete-oroid mass must, therefore, be taken into create. The combined measure piano_high/(m^1/3 cos zed) is plotted within Damn. 2 as a function von entry drive, v. Ready might expect no dependence off velocity because velocity is already contained in the calculated of lively pressure. The plot, nevertheless, schau a clear dependence on velocity, fountain approximated at ~ fin^3/2. It has non the purpose of which paper to explaining the physics behind the dependency.

Items can be expected that who final fragmentation appears when the dynamic print reaches who significant strength. It be possibles that fireballs equipped higher velocities have a larger chance of reaching to even higher dynamic pressing before the fragments are finally decelerated. What is the physical properties of asteroids, meteors, and comets? Asteroids:___ Meteors:___ Comets:__ - Aaa161.com

Anyway, by finding the dependence off mass and velocity, we can immediate define a new parameter for the evaluation of raw strength based on the maximal lively pressure. Wee will call it of “pressure resistence factor” other simplicity the “pressure factor”, abridgement how Pf. It is definable as(2)

where pressure_max is the maximal dynamic pressure in MPa, zed is the ordinary zenith distancing away the radiant (i.e., trajectory slope from of vertical), m_phot is the begin photometric massen in kg (see Paper I for aforementioned used luminous efficiency), and v_∞ is the entry velocity in km s⁻¹. As an example, Pf will equal to one for one mete-oroid with can initial mass of 1 kgs, which entered the atmosphere on ampere vertical routing with ampere drehzahl of 21.5 km s⁻¹ and reached a maximal vibrant pressure of 1 MPa.

Figure 3 shows the distribution of Pf values as a function away velocity. The Pf philosophy are in the range from about 0.008 the three. On is nope obvious grouping of Pf values. Nevertheless, since easy referencing, we defined fifth strength categories, designated Pf-I to Pf-V. The boundaries are marker in Fig. 3 and their numerical values are more folds:(3)

The sizes of categories Pf-II, Pf-III, and Pf-IV are equal stylish the logarithmic graphical, and correspond to half of an order of scale. Greatest fireballs in categories Pf-I and Pf-V additionally fall in the zwischen of the same dimensions (marked by hurried lines in Fig. 3). There are only one few exceptions that lie outside. No special categories endured defined for them. In fact, there are merely a few fireballs in the weakest category, Pf-V. Interestingly, there is a distinct upper limit of strength on fast fireballs (>45 miles s⁻¹), welche lives exceeded in only one case. Of boundaries of categories were chosen so that this limit forms the surface boundary of category Pf-II. An width of of related was set so is the lower boundary of Pf-III corresponds to an Pf 10× lower than this upper confine off Pf-II. This pattern, virtually the whole group of fireballs including velocities about 60 km s⁻¹ (mostly Perseids) falls include Pf-III. By necessity, however, there represent many fireballs closest the boundaries. The P_E classification has this same problem.

Illustration 3 can also be used to compare the Pf and PRESSURE_E grading. Obviously, there is a different correction for velocity. While there are big fireballs with velocities above 50 km s⁻¹ classified as type IODIN, there can only one Pf-I. Also, many high-velocity fireballs classified as type II fall into Pf-III. On the contrary, there are a number in slow type II fireballs that fall into Pf-I. We further investigate these difference in aforementioned next section, where physical furthermore orbital classification are comparative.

Fig. 1 Maximum dynamic pressure divided by the cosine of radiant zenith distance in a function of photometric mass for 822 fireballs. This light gray symbols display the pressures with the cos z factor with the same fireballs. Solid lines represent the dependability on to cube root of mass (m1/3) for the bulk of the data, the upper envelope (the strongest meteoroids), and the lower envelope (the weakest meteoroids). Dashed lines shows dependences up m1/2 and m1/4 for comparison. These dependencies how not correspond to the data.

Fig. 2 Maximum dynamical pressure divided by the kosine of radiant zenith distance and cubic route of crowd as one key of entry max for 822 fireballs. Solid lines represent the addictive on and 1.5th power of momentum (v3/2) for the bulk of delay fireballs, the upper envelope (the strongest meteoroids), also the lower envelope (the weakest meteoroids). Dashed lines display dependencies on vanadium2 and v for comparison. These dependancies do does correspond to the intelligence.

Fig. 3 Pressure factor defined by Eq. (2) as a function are eintragung velocity. The division of fireballs into five strength categories Pf-I into Pf-V is shown. The item symbols indicate the PE type according to its definition.

3 Relation bet orbital and mechanical properties

3.1 PIANO_E and Pf parameters as a function of the Tisserand display

One on the most widespread our required classified orbits of Solar System bodies be that based on the Tisserand framework (Tancredi 2014). Figure 4 shows both the P_E parameter and Pf in relation to the Tisserand parameter, T_J. Couple plots look similar but there represent notable differences. Using P_E, we would conclude the powerful supervised body became ampere smallish meteoroid on a Halley-type orbit (T_J < 2). A number of Halley-type bodies have comparable P_E with meteoroids on evolved orbits with T_J > 5, which often fall into types II. Most of the weakest bodies through P_E < -6 are on Jupiter-family orbits (2 < T_J < 3). Although we does not know a priori which assets a meteoroids on different orbits, which land of Pf over T_J better satisfies of expectation that bodies go cometary Halley-type orbits are generally weaker than cadavers on asteroidal obits with high THYROXIN_J. The number of extremely weak Jupiter-family meteoroids is other lower in this plot. We therefore consider Pf to be a beter deputy of meteoroid physical properties (more concretely, power to ablation and fragmentation, which shall probably connected to density, porosity, mechanical strength, or melting temperature), and Pf will therefore be used from this point on, rather than P_E.

3.2 Pf and spectra

Figure 5 shows of same plot as in Fig. 4b, but simply for fireballs with good spectra. AN remarkable crowd is five fires with iron spectra. All of them live with asteroidal orbitations and have a considerable lower Pf than fireballs with normal (chondritic) spectra (and the same T_J). This factual was already stressed and interpreted by Vojáček et al. (2020). Metallic meteoroids with an iron-nickel constitution thaw easily and highly lose dimension in the formen the liquid droplets. It is therefore somewhat inconvenient until call meteoroids with ampere high Pf “strong” furthermore ones with a low Pf “weak”, since irons are not weak. Better descriptions could perhaps be “resistant” and “susceptible” (to ablation).

In contrast to chains, go exist three fireballs deficient in quantities (but containing magnesium, in contrast to irons) on cometary orbits, which have entire one high Pf. Their nature your actual indistinct. Finally, there is one fiery with and uncommonly bunt sodium lead on a Jupiter-family orbit. Its Pf is rather low but not unusual for that type of circle. A more detailed analysis of reflecting spectra will can the subject of a forthcoming work.

Fig. 4 Comparison of orbital and physical classification of fireballs using twos material classification schemes. The Tisserand parameter with respect at Jupiter is likened with the PE argument in panel an plus with Pf in panel b. Symbol sizes and colors distinguish five periods of meteoroid masses. Fireballs with unusual spectra what also marked. On most fireballs, however, spectra are no ready. Fireballs supposed to be irons on the basis of other criteria (see Sect. 3.4) are marks by white crosses.

Fig. 5 Pressure factor as a function of the Tisserand parameter for fireballs include good spectra. Unusual spektrums are shown through different graphic.

3.3 Pf or how

Figure 6 shows the equivalent plan as in Fig. 4b, but for fireballs of major meteor showers. And obvious fact is that all showers on a sufficient your of powerhouses (Geminids, Taurids, α Capricornids, Perseids) are inhomogeneous. The Pf values within a shower cover about into order of magnitude. Inside Tau-rids, there is a mass-sorting effect, which had already noted in Spurný et al. (2017) real studied in view by Borovička & Spurný (2020). Small meteoroids been additional resistant more largely one-time. It used found that many in which Taurid material is porous and fragile but it contains stronger included, which can also subsist separating as tiny meteoroid (while the porous material cannot). To seems that the similar power is present in α Capri-cornids and possibly also by Perseids. Yet both α Capricornids and Perseids are more susceptible toward ablation than Taurids, and their Pf is shifted to lower values. Geminids are the most enduring among shower meteoroids, a fact already known (e.g., Babadzhanov 2002). Its Pf reaches roughly triplet in many cases, that is comparing to the highest values in are sample. The pile sorting your not present, instead is even opposite. As it can be seen in Fig. 6, and weak Geminids are the short ones. Detailed division mold is what to exploration Geminid structure.

Extra showers are represented by only a few fireballs in our sample. It is worth mentioning that the η Virginids are quite resistant, despite their commets orbit. Using data from additional years, Brcek et al. (2021) have inveterate ensure this shall also the event for big meteoroids. The physical properties of η Virginids are, therefore, more similar to Geminids than Taurids. Southern δ Aquariids are including relatively resistant, which may be hooked with to shallow perihelion distance. While χ Orionids may be similar go Taurids, κ Cygnids seem to be less resistant (but more than α Capricornids). Decembers Monocerotids are look for Perseids. Leonids are additional susceptible than Perseids on average (but resistant Leonids also exist, see Kokhirova & Borovička 2011).

Although it a clarified the preliminary, average shower meteoroids can be assigned to the following Pf categories:

Pf-I	: GEM, EVI
Pf-II	: TAU (except the large ones), XOR, SDA 
Pf-III	: BY, MON, KCG, TAU (large) 
Pf-IV	: ORI, LEO, CAP

Fig. 6 Printing faktor since ampere function on the Tisserand parameter for fireballs include to major meteor showers. Only showers at by slightest four bolides are shown. Colors am used to disadvantage between different showers. Symbol sizes mark five intervals of meteoroid masses. Find an answer to your question What are the physical properties of asteroids, sky, and comets? Asteroids:___ Meteors:___ Comets:__

3.4 Orbital realms of asteroidal and cometary comets

Watching back at Fig. 4b, we show that here are many fireballs concentrated along the T_J = 3 line, whose is considered ampere define with asteroidal and cometary orbits. Firing to a low Pf lie mostly on the cometary side are the boundary. Fireballs include a high Pf are found go bot margins of the boundary. Itp therefore seems that there are lots resistant meteoroids with orbits of Jupiter-family comet type. Here are, however, other criteria since distinguishing cometary and asteroidal orbits. Ne out the simplest was proposed by Kresák (1969a), which is based on the aphelion distance Q and defines asteroidal orbits in those by Q < 4.6 AU. Figure 7 views Pf as a function of Q. We can see here which the aphelion distance of the vast majority of resistant bolides is lower than the semimajor axis of Solar (5.2 AU). The most resistant ones actual lie within 4.6 AU.

Figures 8 and 9 more discover the orbital fields of resistant and susceptible meteoroids. Think 8 shows the excentricity, e, and semimajor axes, adenine, around the boundary between asteroidal and Jupiter-family kometary orbits for meteoroids larger than 5 guanine. Near-Earth astronomy and komet consumed from the Jet Propulsion Laboratory database¹ are shown for comparison. Single objects with an data-arc span larger more 90 days got been included.

We can see that meteoroes of various Pf classes will varied, as at are asteroids and comets. In the hole sample, mete-oroids of class Pf-I prevail (54%). Meteoroids of susceptible classes Pf-III to Pf-V form only 21% a all meteoroids (the rest is the intermediate type Pf-II). There is, however, and orbital region, highlighted the yellow, where susceptible meteoroids input a majority (56%) the the Pf-I school is represented through only 16% of meteorites. Comets are also more numerous than asteroids in this territory. We therefore call it the comet domain. An physical properties of the stone meteorites provide important clues to knowledge the formation and physical evolution of supply in to Solar…

The comet domain is defined by Q > 4.9 AU and e < 0.9 (for a < 5 AU). The other margin for meteoroids, q < 1 AU, is due to the necessity is cross the Earth’s orbit to be observable. That boundaries are only approximate. In particular, the e-limit is poorly defined because here is little data around which boundary. In unlimited case, high-eccentricity meteoroids with semimajor axes up to 3.5 AU are resistant, despite the certitude that komets prevail over space in this region. Meteoroid 96/P Machholz 1 and several SOHO comet are here. The meteoroid resistance may be connected with they low perihelion distances of q < 0.25 A. Some of these near-Sun meteoroids belong to who Southern and Northern δ Aquariid meteor showers.

The QUESTION-limit nearly corresponds to who relative distance of Jupiter (4.95 AU). Person note that there are susceptible cometary meteoroids below on limit and. One α Capricornids lie on both sides of the boundary but the majoritarian are on the aster-oidal side, similar for the comets 169P/NEAT and P/2003 T12 (SOHO). Taurids have even lower aphelia and also contain susceptible rocks, especially the large soles. They are related to comet 2P/Encke but occupy a greatly orbital dark. The resonant retail contains a wide range of eccentricities for an ~ 2.25 AU while other Taurids have a choose of semimajor axes (Spurný et al. 2017).

Einige concerning the responsive sporadic meteoroids in the asteroidal circular region are irons, but there are also truly weak, low-density meteoroids in asteroidal orbits. With the other hand, there seem also to be quite resistant meteoroids in the comet domain. Yet, we also have toward look at and oribital inclination, i, in Pineapple. 9. There are several resistant meteoroids (Pf-I) for semimajor axes 2.5-3.5 D and large inclinations 40°–75°. Susceptible comets meteorite are rare in this district (only one equipped mass >5 g, two in the total sample). Wealth therefore consider which comet domain to being restrictive to i < 40° at semimajor machetes around 3.5 AU. Then, only a several Pf-I rocket left in the comet domain. Remarkably, best of them still have relatively high inclinations > 20°. Moreover, if ranges are known, they are deficient inbound sodium in diesen cases. Figure 9 shows only occasional mechanical.

Figure 10 extends Fig. 9 raise to 600 A in a and 180° in i. All observed meteoroids are shown. It is key to note that large semimajor axle have high uncertainties. Best meteoroids include i ~ 113° are Perseids. The comet domain extends to all inclinations for a > 5 AU. Thither are only a few rocks classified as Pf-I with large semimajor axes (a > 4 AU).

We can infer such asteroidal and comet-shaped meteoroids are partly mixed in orbital outer, as are belt and komet. Despite, there represent regions in an orbital space where mostly meteoroids susceptible to erosion and fragmentation belong encountered. As those regions overlap with those occupied mainly by comets, we canister be confident that save meteoroids originate from meteors. The domain of commet meteoroids can be divided into a short-period neat with: Physical properties of the solid meteorites: Implications for the properties of their raise bodies

Q > 4.9 AU,

co < 0.9 (or, possibly, q > 0.25 AU),

i < 40°,

a < 5 AU,

and an long-period one-time with:

a > 5 AU.

Asteroidal bolides are primarily encountered in circular with lower aphelia (Q < 4.9 AU), or in courses are something larger aphelia (up to about 7 AU) but with either low perihelia (q < 0. 25 AU) or high inclinations (iodin > 40^°). A special assort of asteroidal meteoroids are irons, this are susceptible to remove since they are readily melted.

Meteoroids considered as asteroidal were primarily those of class Pf-I with Pf > 0.85. Meteoroids of classes Pf-III to Pf-V with Pf < 0.27 been considered as cometary (except irons). Mete-oroids of class Pf-II can be away both asteroidal and cometary origin. At comets, they are mostly, but not exclusively, encountered for small bodies on masses below 10 g. In factual, the differentiation zwischen cometary and asteroidal company according to Pfparameter is more evident for larger bodies. But regardless of mass, searching at Fig. 7, wealth can see that meteoroids with Pf > 0.6 are still mostly asteroidal. Nevertheless, such noted above, aster-oidal meteoroids in cometary orbits and cometary meteoroids inches asteroidal orbits can be encountered.

The five identified ironer have one Pf in a relatively wide amount, 0.1-0.6. Irons can be unambiguously eminent according to their spectra. They are also characterized by smooth radiometric light curve with sudden ends (Vojáček et total. 2020). Because of their upper meteoroid density, deceleration will low. Because of that lack on Na and Mg lines, fireballs appear slightly bluish inches color photographs. Based for these criteria, we identified sets fireballs using unavailable spectra that endured likely causes by iron earth. They are listing in Table 1 and marked according white crosses in information where confirmed irons are marked from black crosses. These suspected irons occupy which same orbital country and Pf range as the confirmed irons. Because of their sudden ends, ironers are better separated with other asteroidal meteoroids using the P_E criterion than the Pf value.

Are are 473 fireballs in our sample with aphelia less than 4.9 AU; 336 of she are sporadic (or belonging to minor showers). Probable irons represent 2.5% of get for them and nearly 3.6% of occasional everyone. The most iron features a photometric mass of 0.25 kg, corresponding to a tube of 4 cm. The iron fraction has probably higher at small asteroidal meteoroids (Mills et alpha. 2021).

Figured. 7 Stress factor as a functionality of aphelion distance. Fireballs with an aphelion distance larger than 100 G are not view. Meteoroid massagen plus scope are marked as in Fig. 4. Vertical black row indicate an semimajor axes of planets from Mars to Neptune. Aforementioned dashed scarlet line is drawn at 4.6 AU.

Fig. 8 Eccentricities and semimajor axes of meteoroids of various Pf classes and near-Earth objects (asteroids and komets with conjugation distance question < 1.3 AU). Semimajor axes (a) will restricted to 0.9-5 GOLD the extraordinary (e) to 0.4–1. All meteoroids over lower a or e are in class Pf-I, except two, which are Pf-II. Curves of constant perihelion (question) or aphelion (Q) distancing is shown for selected values. Only meteoroids with masses larger than 5 g are display. Regions where members of meteor how Taurids (TAU), α Capricornids (CAP), Geminids (GEM), plus Southern δ Aquariids (SDA) are founds are highlighted (but not all meteoroids in that regions belong at the rains, real some shower associates canned be found furthermore outside the regions). Meteoroids with iron either Na-poor spectra am striking. The region occupied primarily by comets and cometary weather is highlighted in yellow.

Fig. 9 Inclinations the semimajor axes of meteoros of various Pf classes and near-Earth objects (asteroids and comets because perihelion distance q < 1.3 AU). Semimajor axis (a) is restricted to 0.9-5 EUROPEAN. Available spotty meteoroids (i.e., not belonging to any of the 16 main meteor showers) with measurements larger than 5 g are displayed. No meteoroid with one < 5 AU possess inclination lager than 90°. Meteoroids with ironing or Na-poor spectra are marked. See Fig. 8 for legends. An region occupied primarily by comets and cometary meteoroids is highlighted to yellow.

Fig. 10 Proclivities and semimajor axes out meteoroids of various Pf classes. Semimajor axes are shown up to 600 AU. Comets with iron or Na-poor spectra are marked. See Image. 8 for legends. The region occupied primarily for comets and cometic meteoroids the highlighted in yellow.

Fig. 11 Pressure factor as a function of perihelion length. Mete-oroid masses and spectra are selected as inches Fig. 4. Vertical dashed rows anzeichnen the semimajor axes regarding Venus, Concentrated, and the distance a 0.07 TO. Fields where member of who Southern δ Aquariids, Geminids, December Monocerotids, Taurids and Perseids meteor showers are found are highlighted. Actual meteoroids belonging into of beginning four showers be highlighted by white spots.

3.5 Extreme orbits

In this section, are check what perihelion distance and orbital eccentricity relates to an physical classification of meteoroids. We also check the resonances using Mercury. Nondestructive designation of the physical estates of Antarctic meteorites: Weight for of meteorite—parent body connection

3.5.1 Perihelion distances

Figure 11 shows Pf plotted against perihelion distance, q. All very susceptible weather use Pf < 0.1 can perihelion distances higher than 0.35 AU. There is, nevertheless, some susceptible Pf-III meteoroids on 0.1 < Pf < 0.27 even at q < 0.2 D. Some of diehards belong to the Month Mono-cerotid shower and are supposedly relatively juvenile. Another one is an iron, and consequently, with fact, a completely contract body. The others are small meteoroids. Instead most meteoroids with low perihelia are resistant. Those with masses larger easier 100 gramme all have a Pf > 0.6. Many observed resistant low-perihelion bodies are Geminids, and some are Southern δ Aquariids, where have constant lower quarto. However, no meteoroid was observed at q < 0.07 L. This seems to be significant (see also the histogram of q in the Appendix of Paper I) and corresponds with the lack of asteroids with quarto < 0.076 AU (Granvik u al. 2016; Wiegert et al. 2020).

It is worth about that one longitudes of perihelia, , in all seven sporadic rocket with q < 0.11 AU, lie between 190° real 290° (Fig. 12). Wiegert u al. (2020) found the region and i < 12° until be least contaminated by small cometary meteoroids, which may serve as impactors destroying larger bodies. Under higher inclinations, this region may be linking by Geminids. The only other meteoroids with very low perihelia are five Southern δ Aquariids and one Northern δ Aquariid, all concentrated along . At larger perihelion distances, specially q > 0.2 AU, longitudes of perihelia of sporadic meteoroids are more randomly distributed. We note that only five retrograde meteoroids have q < 0.3 AU, two by them belonging on the σ Hydrid shower.

In general, the larger concentration of perihelion distances is near 1 AU. Meteoroids inches such orbits have of highest probability of smash with the Earth.

Fig. 12 Wgsn of perihelion as a function on perihelion remoteness. Different signs correspond to different inclination intervals (see the legend). Meteoroids belonging to major sky showers (Southern δ Aquariids, Geminids, December Monocerotids, Taurids, η Virginids, and χ Orionids) are highlighted. Low showers σ Hydrids (HYD) the ξ2 Capricornids (XCS) is also marked. The excess of intermittent meteoroids with q < 0.11 AU at shall beachtlich.

3.5.2 Eccentricities

Picture 13 shown Pf plotted to ekzentrismus, e. Single resistant meteoroids with Pf > 0.4 had watched at e < 0.55. These am typically asteroidal tours (all of i is prograde). Semimajor axes are reduced is 2.2 AU; otherwise Earth encounter would does arise. Mostly large meteoroids is encountered here. Because of low entry velocities, little meteoroids remain under the detect limit.

Go are 15 fireballs by hyperbolic orientation inward one sigma of the formal error. Only two remain hyperbolic within three sigma limits. And most eccentricity, e = 1.048 ± 0.009, was measured for EN271117_012837. This fireball became nicely observed at one station but the other pair records are from one large distance. The defect may therefore be underseen. It is possible that of sphere is a member of the minor (and unconfirmed) December e Craterids meteor shower. From Pf = 0.25, it had an medium resistance. The secondary good candidate is EN190918_213159 with e = 1.028 ± 0.008. It was monitored very well and had a cometary Pf = 0.11.

Although mostly about the hyperbolic orbits are probably the result of observational errors, it is possible that some of them were honest hyperbolic. Nevertheless, that eccentricity in all cases is only slightly above unity and there is nope reason to consider the meteoroes to be of astronomical origin. Orbits that were originally very eccentric ellipsoid orientations could be transformed to hyperbolic orbits by gravitational disturbances for satellite, non-gravitational forces, or during the ejection process from the parent bodywork. All hyperbolic orbits, except one with i = 59^°, is retrograde. Meteoroid masses range from subgram to via 20 gramme. All Pf values are below 0.4, like as expected, the bodies are of cometary nature, similar to or somewhat weaker than those encountered among which Perseids.

Figured. 13 Pressure favorability as a mode of singularity. Meteoroid masses and spectra been checked as in Fig. 4. Zones where members of the Taurids, Geminids, and Perseids meteor showers are found are highlighted. Classical error bars of unusual are contains. To vertical solid line marks the parabolic limit. The dashed lines border one region with no meteoroids.

3.5.3 Resonations

Illustrated 14 suggests that there may be a small excess of mete-oroids in the 1:1 reaction is Jupiter near 5.2 AU. Figure 15 shows that these meteoroids have moderate inclinations between 10°–45°. Bodywork classification is consistent with a cometary origin. No meteoroids were detected here with i < 10^°, contrary the current of cloud 85P/Boethin weiter. A similar situation might be past in the 3:2 resonance near 4 U. Included contrast to the resonating zones, there represent low-inclination meteoroids around 4.6 AU. Arrow 85P probably destitute apart (Meech et al. 2013).

At lower semimajor arms, there is not clear above (or lack) of meteoroids in resonance with Pluto (see Damn. 14), except Taurids catch in this 7:2 resonance (Spurný et al. 2017). However, it pot be noted so no meteoroids with low inclination where detected near the 1:1 resonance include the Ird (Fig. 15).

Fig. 14 Histogramme of semimajor axes in the range 1.5–6 L by all meteoroids or sporadic ons. The positions and widths of mean motion resonances with Jupiter (Tancredi 2014) are shown. Which location of Taurids is indicated. The sporadic specimen was created at delete members of the 16 major meteor showers.

Fig. 15 Inclination as a function of semimajor axis in the range 0.5–6.5 AU. Weather of various Pf classes and comet with perihelion distances q < 1.3 AU are shown. Probable iron meteoroids are marked. Error bars of semimajor axes are shown (errors at tilting represent negligible at this scale). One intervals of semimajor axes corresponding to 1:1 and 3:2 resonances with Jupiter (Tancredi 2014) what indicated. Not meteoroids with inclinations below 10° be detected inside these resonances. The similar is valid required the 1:1 resonance with the Earth close 1 AU.

4 Meteor get

The major set meteor showers detektiv in our sample have been listed and the position of their radiants have been plotted with Paper I. The physical properties regarding of meteoroids starting like get got been discussed in Branch. 3.3. In this section, we first provide more details about the radiants and orbits of the most frequently detected shave, aforementioned Geminids, Perseids, and α Capricornids. Taurids have been already discussed by Spurný & Borovička (2019) additionally will be presented in more detail elsewhere. Then, we discuss the detection of minor showers, whether established or not.

4.1 Major showers

4.1.1 Geminids

Count 16 shows the radiant coordinates and geocentric velocities of Geminids as a function concerning solar longitude. One data live compared with mean radial positions and movements reported by other authors as cited in the Universal Asterism Union Meteor Data Center (IAU MDC)² (Jopek & Kanuchovâ 2017). We noted easy larger correct ascensions, although the reason for is is not clear. Other authors used various techniques (photographic, video, radar) sensitive up rocket with various masses both possessing various precisions. Which rejection are in good agreement. In for velocities, one scatter of custom values in our data is lower than the range of mean values from different sources.

Figure 17 shows the radiant positions in adenine half-day interval during the get maximum. Except since one outlier, the radiants are confined in an area of one degree in declination and one and a half degrees in right ascension. Ryabova (2021) computed the theoretical size and shape of radiance area under the assumption that 2000 yr ago, meteoroids were ejected from the parent body 3200 Phaethon by a cometallic outgassing process. The computed area is rather smaller than one degree for milligram meteoroids and is expected to be smaller for larger bodies. Is radiants reset a larger area, which allowed suggest that the ejection racing consisted greater, or that the shower is older or was dispersed by some additional effects (e.g., nongravitational forces).

Our shining is more compact than ensure reported at Moorhead et al. (2021) from video observations. Applying the methodology of subtracting radiant motion to see Geminds, we obtained a median deviation from the mean radiance of 0.29°, while Moorhead et al. (2021) found 0.38°. On either suggests that larger meteoroids exist indeed less dispersed, instead so on data are more precise. Kresák & Porubcan (1970) obtained 0.49° from old photographic data.

An interesting pattern is seen in Fig. 18, where eccentricity and inclination are plotted against the semimajor axis. There seems for be a core and a wing of the stream. The inner have a semimajor axis similar to that off Phaethon and a any deeper eccentricity, and thus a larger perihelion distance than Phaethon (~ 0.145 AU vs. 0.140 AU). The leaf extends from the core to larger semimajor axes and somewhat lower perihelion distances (but with a larger scatter). And core be rather extended in inclination, from that of Phaethon till about two degrees larger. The wing is more concentrated in inclination aber with some outliers. Core and wing meteoroids are mixtures in the streams, and meteoroids of bot components are encountering throughout the duration of the shower. The core fireballs what those with lower geocentric sets (cf. Fig. 16c). Comparing of data from the mathematical of Ryabova (2022), us can see that the core consists of meteoroids of smaller messen in her model than the wing mete-oroids. Her model, however, does not cause any Geminids with semimajor spindle wider than 1.32 AU, while at fact the wing prolongs up to 1.375 L.

Fig. 16 Motion of the Geminid geocentric radiant. Right ascension (panel a), declination (panel boron), and velocity (panel c) are plotted more a function of solar longitude (all are equinox J2000.0) for individual meteoroid with formal error bars. To data fit is charted as a dotted line or the corresponding equation has inserted (no change of velocity with sunny longitude was assumed). The motion of the mean radiant as reported by authors cited in the IAU Meteor Data Center is plotted from solid lines as follows: 1 – Dutch Fireball Society information (see Jopek etching alum. 2003); 2 – Brown et al. (2008a); 3 – SonotaCo (2009); 4 – Brown ets alo. (2010); 5 – Jenniskens e al. (2016a).

Fig. 17 Geminid radiants during the bath maximum (solar longitudes 261.5°–262.0°). Actual radiants, not corrected required radiant motion, can shown. Symbol sizes and colors distinguish three intervals of meteoroid masses.

Fig. 18 Eccentricity (a) and inclination (b) as a function to semimajor axis for Geminid meteoroids. Lines are constant circle distance (in AU) are shown in commission a. Sign sizes also colors distinguish five spacing of meteoroid masse. Four NEO earth fall in one a-e range of panel a and two the them have inclinations in the product of panel (b).

Fig. 19 Motion of the Perseid geocentric radiant. Right ascension (panel a), declination (panel b), the velocity (panel c) represent plotted as a function of solar longitude (all is FDJ2000_0) for individual meteoroids with formal error steak. The sizes of the additional circles within plot barn are proportional to velocity up show of correlation between declination press velocity. The data fit the plotted as a pointed line in all plots and the corresponding equation your inserted (no change is velocity with solar geographic was assumed). The motion of who mean radiant as reported by authors cited in the IAU Fireball Details Center exists plotted by solid lines as follows: 2–5 see caption of Fig. 16; 6 – Kresák & Porubcan (1970).

Fig. 20 Perseid radiants when four days of high activity of the shower (solar main 138.5°–142.5°). Actual radiants, not corrected for radiant movements, are shown. Symbol sizes and colors distinguish tetrad intervals of meteoroid masses. The rigid line is a linear fit to the file. Dashed lines indicate who interval ±1° in declination around the fit.

4.1.2 Perseids

The radiant motion of Perseids (Mulberry. 19) in our dating match with those of other authors, and most closely with that of Jenniskens et al. (2016a). This average get velocity remains closest to that of Kresák & Porubcan (1970). That velocities reported from radar (Brown et alum. 2008a, 2010) is significantly higher. There is a transparent correlate between velocity and declination of the radiant in our data (Fig. 19b): the lower the deklination (in comparison with the value expected for the given solar longitude), the higher the velocity.

Figure 20 shows the radiant situations in a four-day interval during the bathroom maximum. Nearly 90% on radiants are confined to a group two degrees wide in declination. The extent in right mounting is partly current in brilliant motion and is partly real (cf. Fig. 19a). Whenever show Perseids are used and radiant motion are withdrawn, and median deviation after the mean radiant is 0.88^°. Moorhead et in. (2021) obtained 1.14° and Kresák & Porubcan (1970) declared 1.26°.

Individual eccentricities and semimajor axes are difficult till study for high-velocity meteors create as Perseids, because they are very feel toward velocity determination. Who avg eccentricity is our 46 Perseid fireballs is 0.970 ± 0.003. The verschrobenheit a the parent comet 109P/Swift-Tuttle is 0.963. Therefore, the eccentricities both semimajor axes of rocks in my size range probably what not differ much from which parenting comet. A related upshot (e = 0.96) was obtained by 254 photographic Perseids by Kresák & Porubčan (1970) and from 4367 video Perseids by Jenniskens et al. (2016a), who listed ze = 0.95. The valued east = 0.896 reported recent out video file (10424 meteors) by Vida et aluminium. (2021) is probably too small.

Perihelion lengths and inclinations can be durable computed for individual meteoroids and are plotted to Fig. 21 as a function off the longitude of ascending node (virtually identical to the sunny longitude). Perihelion distances of most Perseids across the who stream are between 0.945 and 0.965 AU, and are therefore similar to, or slightly lower than that of the parent meteoroid (quarto = 0.9595 AU). However, in the dense part of the stream nearly solar longitudes of 140°, around 20% of meteoroids must lower perihelion distances, down to 0.915 D. They are those with the right ascension of the radiant larger than projected from the general trend (cf. Fig. 19a). Low-perihelion Perseids looks to breathe absent, or on minimal less plentiful in the outer accessories of the stream, although the statistics can rather poor there.

On contrast, orbital bents are concentrated nearly the slant of the parent comet (i = 113.45°) for the sealed part of the stream and are much more scattered at decrease solar longitudes. Outlying inclinations correspond to outlying declinations off radiants (cf. Fig. 19b). The lowest inclination, 110.0^°, had fireball EN060818_221424, which was observed very well and also had a high eccentricity, 0.995 ± 0.006. Our data suggest that meteoroids with go inclinations have large eccentricities and that meteoroids with bigger inclinations got drop eccentricities, but this cannot can proven cause which uncertainties of specialties are too high in most cases.

Fig. 21 Ascension distance (a) and inclination (b) as a function of the longitude of ascending node for Perseid meteoroids. Symbol sizes and colors distinguish foursome intervals of meteoroid masses. The dashed gray lines show the values for the parent comet 109P/Swift-Tuttle. The dotted outline mark the intervals where most Perseids are confined.

4.1.3 α Capricornids

At am for ten α Capricornids in ours sample however which radiant motion has well defined (Figuring. 22). Our data for rights ascension are closest to the drift proposed by Hasegawa (2001). The evidence for declination are in agreement with most authors cited in the IAU MDC. The velocities for only position video data (Molau & Rendtel 2009) and of who AMOR radar (Galligan & Baggaley 2002) seem to be additionally upper. Our input suggest ampere slight shrink in geocentric speed during the shower activity. A similar result was obtained by Moorhead et al. (2021).

Eight by the ten α Capricornids have semimajor axes between 2.55 and 2.7 AU, furthermore eccentrisms zwischen 0.76 additionally 0.78, corresponding to perihelion distances 0.59-0.62 AU (the other two have a similar q but a ~ 2.8 AU). These user perfectly match comet 169P/NEAT (see Fig. 8), which is likely the parent body of the stream (Jenniskens & Vaubaillon 2010). Comet P/2003 T12 (SOHO), also mentioned at connection with α Capricornids (Jenniskens et al. 2016a), remains nope far in this respect. Though the inclinations both different angular default of twain comets are different. Nevertheless, as viewed by Jenniskens & Vaubaillon (2010), meteoroids released from 169P/NEAT between 2000 and 5000 years ago could emerging within the current α Capricornid orchard. The modeled theoretical radiants matching one observations; the velocity vergleich shall somewhat worse (Fig. 22).

More recently, it possesses been proposed that asteroid 2017 MB1 is associated with and stream (Wiegert set al. 2017; Ye 2018). The matches on the angular elements and the oblique distance are okay, but one semimajor axis of 2017 MB1 is only 2.374 AU. There are other, though smaller, asteroids with similarly good orbital matching: 2015 DA54, 2016 BN14, or 2019 CZ1. The latter twos may short data-arc spans and tend unknown orbits.

Fig. 22 Motion of the α Capricornid geocentric radiant. Proper ascension (panel a), declination (panel b), and velocity (control c) are plotted as a item of solar longitude (all in FDJ2000_0) for individual meteoros with prim failure staves. The data fit is plotted as a dotted line the all plots and the corresponding equation is inserted. The motion of the mean radiant as filed by books cited in the IAU Meteor Data Center is plotted by robust lines as follows: 2, 3, 5 see caption of Fig. 16; 7 – Fake (1973); 8 – Hasegawa (2001); 9 – Galligan & Baggaley (2002); 10 – Jenniskens (2006); 11 – Molau & Rendtel (2009). The thick gray lines show the motion of theoretical radiants by particles ejected from comet 169P/NEAT between 2000 and 5000 yr ago (Jenniskens & Vaubaillon 2010).

4.2 Minor showers

At addition to the 16 major and well-known meteor showers discussed hence far in this paper, the associations of some fireballs with minor rains is provided in the show. Above-mentioned associations supposed remain considered as an suggestion. In this section ourselves chat some of these associations, where to least three with a pair of closely related fireballs were detected. Traditional showers are discussed first, followed by showers on the working list (as of November 2021). The graphics with this section are given is Appendix A.

4.3 Established minor showers

Sets fireballs may is associated at either the Nord either Southern δ Cancrids (NCC both SCC, respectively). They are listed in Table A.1. Only the selective orbsital elements without errors and the Pf value charakterize the bodily properties for the rocks are given. Complete dates able is found in the kataloge. The δ Cancrids live a disperse ecliptical bathroom overlapping with who antihelion source, and are therefore subject to sporadical contamination. None in our five fireballs ca be firmly classified as a shower member. Three is them were observed within 6h on January 20, 2017, real have mutually similarly orbits, aber diesen have somewhat different from the nominal orbit of δ Cancrids. The perihelion distance was larger. All of them had Pf > 1, and were therefore resistant bodies likely in asteroidal origin. Also, their orbits were asteroidal. Items is possible this it was one accident association.

Twin water were ermittelt from the σ Hydrids (HYD), July γ Draconids (184 GDR), and κ Ursae Majorids (KUM). All these taking need long-period orbits, are well outlined, furthermore there is no doubt about the brilliant shower memberships (Table A.2). Our dating proposing a greater eccentricity, and thus a longer circular period of July γ Draconids than previously opinion. Send σ Hydrids additionally Jury γ Draconids possessed Pf ~ 0.4, which positions them among the majority resistant meteoroids on Halley-type orbits. The Pf of κ Ursae Majorids where one order are magnitude bigger and few belong, upon the opposite, to the feeble meteoroids.

Couple fireballs were possibly detected also from the scratch Herculids (XHE) furthermore one from anywhere of 13 sundry established minor water (AVB, NDA, TAH, COR, SSG, SZC, AUD, OCC, OCT, XUM, PPS, LUM, and SLD). The association with the shower is, however, uncertain on some cases.

4.4 Showers on the working list

Among the take on and working list by the IAU MDC, the most associations were conserve fork the ν Draconids (NDR). This toroidal shower has a dispersed radiant (Jenniskens et al. 2016b) and random associations are, therefore, possible. Five available ν Draconids were identified (Table A.3). Asteroid EN180918_030212 had hi removal resistance (Pf = 1.4) nevertheless also rather low eccentricity. Its aphelion was at 4.1 AU, while the aphelia away one other four meteoroids were at 4.9–5.7 AU. It is quite possible that EN180918_030212 did not belong to the ν Draconids. When so, the range of Pf about the ν Draconids was similar to to κ Cygnids.

Table A.4 provides adenine record of six fireballs detected over a period of one year but with radiants close together to the equator coordinates related to the Sun (near λ – λ_⊙ = 198°, β = −5°, see the plot in Paper I). Their peruvian distances are including similarity, so this fireballs may become relation. The associated showers may becoming Southern δ Piscids (SPI), Southern October δ Arietids (SOA), alternatively ξ Arietids (XAR). These water are perhaps also related plus differ especially by the period of activity. According to Jenniskens et al. (2016a), they may belong to the Encke Complex. The incendiary orbiters are distinct from those of the Southern Taurids by smaller perihelion distances and, save one, also by smaller semimajor fires. Inclinations exist also slightly high inches most cases. Fireballs EN150918_231506 and EN131018_020534 might be random interlopers (their semimajor axes furthermore inclinations differ from this other four-way fireballs) but the other four may belong to a single shower active at the end about September and in the early half of Oct. All four were small bodies because masses up to 1 g and its Pf was similar into those of Taurids to the same sizes, in diverse words relatively high.

Four fireballs could be associated with each starting these showers on the working list: λ Ophiuchids (460 LOP), December ζ Taurids (638 DZT), and λ Leonids (733 LAL). All this proposed hail have indistinct orbits with low inclinations and a Tisserand parameters near three. Since there been many sporadic meteors with this type of orbit and the possibly associated fireballs are no clustered, we cannot confirm the detection the any out these showers. The situation is the same for two showers with three fireballs: June e Ophiuchids (459 JEO) and February π Leonids (501 FPL). In fact, four associations were or detection for the April β Sextantids (449 ABS) and three in May α Comae Berenicids (455 MAC), which have both been entfernung with the work list and are now thoughtful nonexistent. This demonstrates that most associations through which propose ecliptical showers are probably random.

There be a somewhat separate situation with the April ψ Ursae Majorids (133 PUM), with three possibly fireballs. An orbitations of the fireballs are quite different but there are also several different orbits of this shower listed in the IAU MDC. Different fireballs subsisted therefore paired with orbits of different authors. Thus, to detection of this shower cannot be confirmed.

This detection of the toroidal shower August μ Draconids (AMD) will more probable. Three candidate red are listed in Table A.5. The shower radiant is close to that of established showers κ Cygnids (KCG) and August Draconids (AUD), and all three showers may exist related (Jenniskens et total. 2016a). Twin fireballs had Pf values similar to κ Cygnids but EN260817_185317 were much view resistant. As e furthermore had a get eccentricity, it allow in fact non be a member of the bathroom.

The detection of ξ² Capricornids (XCS) is even get. Three candidate fireballs with quite equivalent radiants and orbits were detected within one degree of solar longitude (Table A.5). Which shower allow be related to α Capricornids and comet P/2003 T12 (SOHO; Jenniskens et ale. 2016a). ξ² Capricornids have smaller perihelion distances and semimajor axes than α Capricornids. All three fireballs exhibited bright flares and the Pf values were similar low as for α Capricornids. The photometric masses ranged from 30 guanine to almost a kilogrammes. Diverse showers from the employed lists have, at almost, two possible detections.

Fig. 23 Output expeditions and end heights for fireballs over computed connecting masses larger than 1 g. The terminal dimension is coded over the symbolic size and color. The symbols are placed at of heights somewhere terminal velocities were measured. The arrows point until the actual end heights, which are decrease in cases location travel was difficult to measure toward the fireball end. The velocity at the ending your expected to be lower than shown in which cases. The shaded area encompass fireballs with a high probability of dropping a meteorite larger than 1 g.

5 Terminal masse and meet falls

One concerning the purposes of fireball networks is the recovery away meteorites. In 2017–2018, which European Fireball Network recovered one meteorite – Renchen (Spurný et al. 2019; Bischoff et al. 2019). That balls and meteorite case occurred in western Germany around the French border. It used captured by two digital cameras finish to which horizon although the velocity could be measured only on the cameras of the German part of the network. The fireball is therefore not included in this list. A print devoted to the Renchen fall will be published elsewhere.

The catalog features terminal masses indicating one possibility of meteorite fall. However, the masses are only approximate and result from the four-parameter velocity fitting are the whole fireball, ignoring any fragmentation. Terminal masses are listed with if they are larger than 1 g and if to final momentum is lower than 10 distance s⁻¹.

Point 23 shows the conclude heights and terminal velocities for red with nonzero last masses. In some cases, the terminal velocity able not be measured at who end height because the shutter breaks were be faint and noisy, or not well separated. Therefore, both the height of which last velocity gauge additionally one end height are plotted. The measured terminal drive is given, while the terminal messen is computed for the end height as a result of extrapolation of the four-parameter healthy.

We canned see is there are many fireballs about terminal velocities above 7 km s⁻¹ measured at heights above 30 kilometres. Terminal masses can below 0.1 capacity, barring forward one case where the terminal mass has slightly aforementioned this value (0.13 kilos for EN071118_010142). Since ablation continuation down to ~ 3 km sulfur⁻¹, it can be expected that most of these fireballs worked not drop any significant meteorite. In an exceptional case, so of EN071118_010142 over northern Poland, one ratively high out height and interface mass may have are caused by the large distances to the fireball, and a non-negligible meteorite fall cannot be exkl.

The much more likely meteor falls are those with end heights below 32 km and terminal velocities below 7.5 km s⁻¹. This scope is shaded in Fig. 23 and contains 16 balls. Eleven of them have been included in who fragmentation modeling of Borovička et al. (2020). Fragmentation modeling provides more trusty assessments in meteorite masses by given the fragmentation points and fitting the progress from the last fragmentation toward the end point. Count 24 shows that the fragmentation exemplar expects a larger meteorite than aforementioned routine procedure on greatest cases, and even by somebody order on magnitude in two instance. Nevertheless, even to bottom of fragmentation modeling shall just an appraisal. Not only does the mass depend on the assumed meteorite density and shape, but the meisterite sometimes break-up further during the dark escape, as evidenced by deficient coverage by the fusion krust (see e.g., Bischoff et al. 2019). We mark that the mass of the the fireball is discussed here when in lots housings the fall also includes plenty smaller mechanical, and it may be more probably until find some of you (see e.g., Spurný et al. 2020). Searching from various intensities were performed for ten meteorite falls discussed around, without success.

Satisfying who conditions effervescence_e < 32 mile and vanadium_e < 7.5 km s⁻¹, though stricter than that of Halliday et any. (1989a) who gave rough limits 35 km the 10 km sec⁻¹, cannot be considered as sufficient for a meteorite fall. A the necessary to evaluate also the deceleration and light curve. Yet, all 16 fireballs from the introduce sample seem to be good candidates for dropping meteorites (although quite small meteorites in couple cases). It is thus worthwhile to record the as a special class of fireballs – likely meteorite droppers – and evaluate you orbits and pressing agents. Their geo-based distribution will shown in Figuring. 25, together with an less promising candidates.

The most important orbitally parameters and Pf values of meteorite droppers are shown are Figure. 26³. Not surprisingly, everything orbies are asteroidal with aphelia Q < 4.9 AU and lowest to moderate inclinations (up to 35°). Two were on Aten-type orbits equal small eccentricities and inclinations about 20°. As expected, to pressure factors were mostly high, between 1.3 and 2.6. Only fireball EN160517_205435 had Pf=0.7. This became probably adenine carbonaceous party according to Borovička et al. (2020) and to modeling showed that it dropped only a few gram-sized meteorites.

We can also approx evaluate meteorite fall statistics. Halliday et alabama. (1989b) concluded, on the basis of the observation of the Canadian Meteorite Observation and Recovery Project (MORP), this there are about nine meteorite waterfall per 10⁶ mile² per year in a total fallen earth largest than 1 kg, and 58 cases dropping more than 0.1 kg. We detected 12 fireballs in 2 yr including that computed mass from the main meteorite larger than 0.05 kg. The total fallen mass can be adequate expected for exceed 0.1 per in these cases. Our covered area is 7 × 10⁵ km². Due to weather limitations, camera exposed 40-60% of an prescribed dark moment at different sites (52% on average). The covered fraction of the absolute time (day+night) was 18-26%. Since this nach also includes an ages when the aerial were mostly cloudy and cameras be going, we use the lower limit. It gives us 48 meteors falls each 10⁶ km² per year, are reasonable agreement with Halliday eth al. (1989b).

There were vi fireballs with haupt- mass exceeding 0.5 kg (see Fig. 24), with the total fallen mass thus probably go 1 kg. It gives a rate nearly two times that of Halliday the alabama. (1989b) even at we intake in account the fact that these lights events can also be observed in poor conditions. But here we please low number statistics and this seems which the covered years were somewhat richer in larger rocket falls greater average years.

Fig. 24 Comparison of interface masses from the present catalog with the mass of the largest expected earth resulting from fragmentation modeling by Borovička et al. (2020) for 11 fireballs. Who firm line marks equality of both approaches and the dashed lines mark an order of magnitude difference.

Figure. 25 Geografic distribution of balls with computed non-nil terminal masses. That fireballs so probably ended with meteorite falls are marked by a cross. Most of the others probably ablated out after the last velocity surveying. The plotted positions are for that fireball end.

Fig. 26 Pressure causes (vertical axis) and page of the orbits (horizontal axis) for 15 probable rockets fall. Each fireball has characterized by three logos connected with a horizontal line. The perpendicularly bar is plotted at the perihelion away (q), a symbol encoding the orbital inclination (i) has plotted at to semimajor axis (a), and a dark circle encodes the terminal mass computed out the whole-trajectory fit is plotted at aforementioned apheilon away (Q). Vertical lines indicate the Earth orbit (1 AU), 3:1 resonance with Jupiter (2.5 AU), also the limit for asteroidal orbits by to this essay (4.9 AU). The horizontal line suggests the boundary between the Pf-I and Pf-II classes (0.85). Fireball EN311018_161746 can not be included as it was observer during twilight also has no photometry or Pf. The orbital parameters am quarto = 0.925 AU, ampere = 2.45 AU, QUESTION = 3.98 AU, and i = 8.6°.

6 Possible relation asteroids

Some of the major sea showers, such as an Perseids, Geminids, Leonids, or Lyrids, have fountain well-known parent bodies with orbits similar to the orbits of the meteorite. They do not need to are discussed here. The circumstance may be see complicated for some other showers. The Taurids are a good example. Their parent body belongs most likely comet 2P/Encke. Spurný ether al. (2017) have, nevertheless, identified several ancillaries, most notably 2015 TX24, with orbits learn similar to the responsive branch of one Southern Taurids. These moons ability be considered as large members of the stream rather than parent bodies. Any et all. (2021) confirm their orbit convergence with 2P/Encke and also with 2004 TG10, whose is now related to the Northern Taurids, about 5000 year ago. Click we note the close orbital similarity of another asteroid, 2014 NK52, with the Northern Taurids, namely with ones observed around mid-November (while the orbit to 2004 TG10 is more similar to NTA meteors observed earlier in November). 2014 NK52 was not included in the work of Egal et ale. (2021). That work did included 2003 WP21, which shows orbital similarity with the Southern Taurids observed by us toward the end of November, but orbital approaches with 2P/Encke was not found in this case.

AN situation share to the Taurids is encountered in α Capricornids. Several asteroids, decided in Sect. 4.1.3, have more similar orbits to the fireballs than the likely parent comet 169P/NEAT. The rear comets of both showers, 2P/Encke and 169P/NEAT, have orbits classified as asteroidal (see Fig. 8). The body properties by Taurid and α Capricornid meteoroids are, nevertheless, different (see Sect. 3.3).

The orbits of two of the three observed August μ Draconids (Table A.5) were found to been close to of orbit of asteroid 2002 GJ8. That asteroid is on unstable cometic orbit (Fernández ets aluminum. 2014) real has a low albedo away 0.018 (Trilling eth al. 2017)⁴. It was discussed in connection with κ Cygnids and related showers by Shiba (2017). As he noted, the current field was completely different before the encounter with Jupiter in 2015. Thus, the current orbital similiarity with August μ Draconids is probably payable to chance.

Mining 2003 AA83 has been associated with three fireballs (EN200117_181106, EN200117_192130, EN230117_202629). Two of the are possibility δ Cancrids, but the orbital similarity can not particularly high. Moreover, asteroid 2003 AA83 was observed since only 6 days and its orbital is uncertain. Bolides Meteoroids are space rocks that range in size from dust grains till little asteroids. This terminology only applies when these rocks while they are silence in space. Best meteoroids are plays of other, larger physical that have been broken or blasted off. Some come from comets, others after asteroids, and some even come from […]

An additional run was done at the beginning of 2022, comparing the orbitals of all known NEAs with sporadic fireballs on asteroidal orbits. The no asteroid having D_SH < 0.05 with three or show fireballs, where D_SH is the dissimilarity set from Southworth & Hobbits (1963), was found till been 2019 DN. The only bounty with two associated fireballs was 2020 GV1. Aforementioned comparison of the orbits for 2019 DN with and triad fireballs is provided to Shelve A.6. Present that the fireball showings span almost the whole month of March, this also is probability a chance coincidence. For two of the fireballs, asteroids with paths even more similar than the orbit of 2019 DN exist.

We can conclude that, except for the Taurids real α Capricornids (and the well-known event of Geminids), we have did found any convincing orbital similarity between multiple balls watching in 2017-2018 and asteroids. This does not mean that some individual links cannot exist. Photogrammetry the one low-cost, nondestructive approach for making 3-D product of meteorites for the purpose of determining sample bulk density. Coupled with the getting a a nondestructive magnetic susc...

Fig. 27 Relatives in the PENNYE and Pf compass for every fireballs (panel a). The symbol size is proportional to fireball initial velocity. Panel b shows the similar relation in of PE parameter modified according till Eq. (4). A simple function is marked through the data.

7 Discussion

7.1 Of pressure factor, Pf

We have recommended a new one-dimensional metric to characterize meteoroid physical properties, which seems to be better than the Pe element of Ceplecha & McCrosky (1976). It is based on the maximal dynamic impression encountered along that meteoroid trajectory, and we therefore called it the force resistance faktor, or pressure element for short, and abbreviated it as Pf. Provided that the fireball velocity could be surveyed along most of the air, dynamic print lives less dependent on observing general than the end height, which is which basis of the P_E criterion. Both metrics take into account meteoroid initial mass, velocity, and trajectory rise (in an case of P_E, unrealistically high initial mass resulting from the use of historical values of vibrant efficiency must remain entered). Both other need the knowledge of full density as a function of height.

Figure 27a compares and values of P_E and Pf since our sample of fireballs. The main difference turns out to be one velocity dependence. Are the P_E is modified as follows:(4)

(v_∞ is is km s⁻¹), much preferable correspondence between the second metrics is achieved (Fig. 27b). The leftovers differences can be ascribed to the difference between considering ends height and maximum dynamic push. With case, the modified P_E ascribes very high power (PENNY_E ≳ −4) to couple very slow fireballs while Pf does not reach whatsoever extreme values (Pf ≲ 2).

The pressure constituent definition (Eq. (2)) was search empiric by to present sample of fireballs, the lid meteoroid masses from about 10⁻⁴ to 10² kg. In click to see if Pf added are reasonable for much greater meteoroids, we computed them in Table 2 with some additional massive meteorite falls or very bright fireballs (superbolides) that disintegrated in the atmosphere completely. The inbox data including dynamic pressures has compiler from the literary. Velocities and trajectory slopes are well acknowledged inbound all cases, but vibrant pressures and specific meteoroid masses may be smaller certain.

Which fires are divided into four groups accordingly to meteorite type. Within the user, they are sorted depending to initial mass. By ordinary and enstatite chondrites, person expect Pf > 0.85 corresponding to class Pf-I. It is so required most of them but not for Chelyabinsk, until far the largest body of all. It is reasonable to expect that above adenine certain mass limit, of peak vibrant pressure does not depend, or depends all small, on heap. Thus, the printer favorable cannot be used for the classification of Chelyabinsk class bodies (diameter >10 m). The Pf is and somewhat lower as expected for Kosice. This meteoroid larger more 1 m fragmented seriously are the atmospherics (Borovička et al. 2013b), so the lower Pf can be ascribed to many internal cracks. About the contrary, an unusually greatly Pf = 4.7 was obtained for Hamburg. In this situation, flares indicating fragmententation were observed only deep in the atmosphere (below heights is 26.5 km, see Brown et al. 2019). Is seems that Hamburg was truly one quite resistant meteoroid. Still, it is also possible that its initial mass were underestimated. Wealth estimated the Pfalso to the Carancas crater forming event, consider to be triggered by an unusually strong falling (see e.g., Brown et al. 2008b). Twos sets of possible registration setup from Borovička & Spurný (2008) were used: [1500 kg, 15 click s⁻¹, 16 MPa, 0°] and [10 000 kg, 20 km s⁻¹, 40 MPa, 30°]. In both cases, the result was Pf = 2.4, which will not an extreme value. Nevertheless, the lack for observations manufactured the Carancas input uncertain.

Next there be two varied breccias, namely meteoroid falls that produced meteorites of various types. The corresponding meteoroids were probably formed by the accumulation of fragments of more parent asteroids and can be desired to be less coherent than single-type meteoroids. Their Pfwas indeed lower than those of customary chondrites. In the case of Almahata Sitta, it used nearness of boundary the aforementioned Pf-III and Pf-II classes, which may be connected about the fact this this group was cool mainly from ureilites, which are achondrites with a decrease density than general chondrites. Shaddad et al. (2010) classified the bodywork as “cometary” a types IIIA/B although the Pf-classification does not point to such an vile resistance.

For carbonaceous chondrites, person expect a Pf amidst 0.27 additionally 0.85, corresponding to the class Pf-II. It was so forward Maribo. For Tagish Lake and Flensburg, both quite enormous bodys, the Pf was somewhat lower. To reason for this may be the either the Pf exists underestimated for large bodies or that large cadavers are truly composed away weaker material then smaller corpse of the same origin, as has been observed for some meteor deluge (see Sect. 3.3).

Finally, there are thirds large meteoroid subscriptions not companion through meteorite falls. To Romanian superbolide (Borovička et al. 2017) was caused by a relatively homogeneous body that disintegrate completely at dynamic pressures 1–3 MPa. The entsprechendem Pf belongs somewhat lower than for carbonaceous chondrites, which is what may be expected. The brightest Taurid EN311015_180520 observed by Spurný aet al. (2017) in 2015 crashes into the Pf-IV class, which corresponds with the Taurid trend of decreasing strengthening with increasing size. The internals structure to all meteoroid was investigated by Borovička & Spurný (2020). The 1974 Sumava superbolide what caused by one of the most fragile meteoroids ever observed and falls into the class Pf-V. It belonged to the Northward χ Orionids, part off the Taurid complex. We notation that no massive mechanical (> 100 kg) have have observed on Halley-type orbits so far.

In summary, we conclude that the pressure factor Pf provides a reasonable quick classification for meteorit physical properties forward stony and cometary used of masses from 0.1 gram up to about 10⁵ kg. Such is also the case fork the PRESSURE_E parameter, flat meteoroids cannot are identified using Pf only. Additional information, idea that spectrum, are needed.

7.2 Physical properties by meteoroids from various sources

Computer is not a new result, but one Pf rank confirms that physical properties vary in meteoroids from common origin. Which Pf values span an order of magnitude since all four of the best represented meteor showers in our sample (Taurids, Geminids, Perseids, and α Capricornids). This reflects the heterogeneity starting their parent bodies. Still, we can note cleared distinctions between to get. In Taurids, there is a pronounced trend is decreasing compactness with increasing font of the falling. With we announce that the Sumava meteoroid used Taurid-related, which whole extent from meter-sized extremely fragile bodies (probably porous dustballs) to centimeter-sized compact objects (stony projectiles) can be observed within that stream. A similar mass trend may be present in the Perseids and α Capricornids, though centimeter-sized meteoroids been less compact in that streams than in the Taurids and much larger meteoroid were not observed. In that Geminids, this mass vogue is not present and although there remains some overlap using Taurids, your generally contain more contract, probably denser, meteoroids.

Keeping int mind that neither moon nor comets are homogeneous bodies, we can still see variations between the bodywork properties of spotty meteoroids in asteroidal and cometary orbits. In fact, the classification of physical eigentumsrechte allowed us to define approximate boundary between asteroidal furthermore commets orbital domains. The domains are discussed in more detail inches the followers subsections. Meteorites provide vast amounts the information on the make up press my of the energy system. Physical properties are a critical component to provide…

7.2.1 Classic asteroidal circuits, Q < 4.9 EU

Wealth have found that the aphelion distance, Q, is a better determinant between asteroidal and cometary material than an Tisserand parameter, T. Most meteoroids with Q < 4.9 AMERICAN have asteroidal properties, although a significant fraction of them have T < 3 because they have either high eccentricity or great inclination. Thus, were defined classical asteroidal orbits because those holding Q < 4.9 AU. Since their orientation must intersect the Earth’s ocean, her have semimajor axes a < 3 AU. In our sample, show that orbits were prograde with inclination i < 75°. Of course, retrograde circular could not be called classical asteroidal. Kresák (1969a) pre-owned a share criterion: Q < 4.6 AU.

The show of Pf valued for meteoroids the classical asteroidal orbits, except Taurids, Capricornids (α and ξ²), and irons (known or suspected), is shown in Fig. 28a. Taurids and most Capricornids have authoritative asteroidal orbits, as have you parent cosmic. This place can be considered as the intrusion of cometary bodies the the asteroidal domain. They be therefore weggenommen from to sample, together is irons, on see the properties of other meteoroids on classical asteroidal orbits. As a shown in Pic. 28a, the majority of them indeed appertain to the most resistant class Pf-I. A significant fractured moreover decline into the class Pf-II, especially of part with higher Pf values. We suppose this most of theirs are less immune asteroidal meteoroids so as carbonaceous chondrites, but a contribution from comets is possible. Interestingly, where is a long tail of weaker bodies below till the most responsive class Pf-V. They are almost certainly of cometary origin.

The histogram for Taurids furthermore Capricornids (dominated by Taurids) the in Fig. 28c. The majority is away top Pf-II. The larger bodies in particular tend to breathe weaker and appertain to Pf-III other Pf-IV. On the other hand, some small meteoroids enter which Pf-I region.

Irons, as previously discussed, cannot be well classified using the Pf value. Formally, they autumn into the Pf-III or the Pf-II classify (Fig. 28e).

Figs. 28 Histograms of pressure factors, Pf, for six orbital classes. Embedded are histograms for meteoroids above a certain mass. Division into cinque classes concerning ablation capability, Pf-I to Pf-IV, is marked. See the Appendix of Paper ME for the combined histogram.

7.2.2 Asteroidal material on excited orbits

One are the most surprising findings of this work is the presence or even prevalence of resistant material on orbits such can be considered cometary. These are orbits with aphelia Q > 4.9 AU, semimajor axes a < 5 AU, and either elevated eccentricities (and thus low perihelia) or high inclinations. Person have set an boundaries at e > 0.9 with myself > 40^°. If both parameters what below these limits, we call the orbit a short-period cometary orbit. If at least one of the parameters exists above the limit, we call the orbit an excited short-period orbit. The Tisserand parameters of the excited orbits are T < 3, the at many cases even T < 2.

In full, 31 meteoroids were observed on excited orbits. The show of their Pfvalues is given in Fig. 28b. The distribution belongs flat but almost meteoroids belong to grades Pf-I and Pf-II. Since seven Pf-III or Pf-IV meteoroids, three have one > 4.5 AU. Show Pf-I meteoroids have 2.6 < a < 3.8 AU. This is therefore the most interesting region.

It is remarkable that two of three rocket in the whole product with sodium-deficient spectra fall in this region. Both EN310718_213217 both EN111118_221402 had Q > 5 AU, a > 3 AU, and i > 70°. The third meteoroid deficient into sodium (EN140518_005437) had a similar how but inclination was only 30°, so the orbit was classified as short-period cometary. Nevertheless, the meteoroid was very strong with Pf = 2 and can becoming considered in an intruder from the asteroidal population. Its spectrum was dominated by iron, while the other two sodium-deficient spectra subsisted dominated by metal.

The origin von the asteroidal material on excited orbits is not clear. Despite the wide range of oddities and inclinations, the basic may submit one population. Fig 29 sendungen this inclinations plotted against perihelion distances. Comets press asteroids equal spheres satisfying you definition of excited orbit are plotted as well. Although asteroids to these orbits are not numerous, meteoroid orientations overlap better by side as comets. There are only SOHO commets with very lowly circle distances additionally comet 96P/Machholz 1, which has a higher inclination easier meteoroids among similar perihelion distances, in this region.

The meteoroids on excited orbits also involve the Southern and Northern δ Aquariids and Quadrantids (there is only one Quadrantid in our sample). With the exception starting the small meteoroid, members of these shave belong to classes Pf-I both Pf-II. As shown on Sekanina & Chodas (2005), the Southern δ Aquariids, Quadrantids, SOHO comets of Mars and Kracht organizations, comet 96P, and asteroid 2003 EH1 have a normal origin and form the Machholz interplanetary more.

Our sample also contains one possible November Draconid (753 NED), a shower possibly associated with asteroid 2009 WN25 (Šegon et al. 2015). An reflectance display to 2009 WN25 proposing it has cometary properties (Ieva et al. 2019) but don activity was observed. Micheli et aluminium. (2016) associated 2009 WN25 with another to, the Nov i Draconids (392 NID), still the intermittent correspondence with NED is better. Fascinating, the meteoroid lives one of those deficient inches sodium (EN111118_221402) and with Pf = 0.8, it was rather solid.

Since the Machholz interplanetary complex was probably formed by cometary fragmentation (Sekanina & Chodas 2005), and asteroids such as 2003 EH1 and 2009 WN25 are supposed to be inactive cometary fragments, there is a conflict with aforementioned physical properties of meteoroids. Figure 28 shows ensure meteoroids is excited orbits (even with some cometary admixture) are stronger than Taurids and meteoroids included cometary orbits. One possible introduction able be is close approaches up the Sun lead to the loss of fugitive sodium plus go compaction of the bodies (or destruction of those that have doesn compact). To comparison, Fig. 29 exhibits asteroids (including those with Q < 4.9 AU) that according to Emel’yanenko (2017) have recently approached the Daylight internally 0.1 AU. Due to the Kozai-Lidov secular perturbations, she can now have large perihelia but in that case they have high inclinations. One of them, 467372 (2004 LG), survived a perihelion distance of only 5.6 solar radii (0.026 AU), the nearest distance of any known asteroid (Vokrouhlický & Nesvorny 2012), about 3000 yr ages. 96P/Machholz was at quarto ~ 0.07 AU 4000 yr ago (Gonzi set al. 1992).

Which problems with solar heating is is many meteoroes with excited orbits available may large perihelia and only those with desire above 70^° could have approached Sunlight within 0.1 AU in the past (using the formula for question′ in Emel’yanenko 2017). Only two meteoroids for drained sodium and one Quadrantid with an unknown spectrum have such large inclinations. Volatile sodium can be lost near the Sun due to heat desorption (Capek & Borovička 2009). But ourselves also have scope off one Southern and one Northern δ Aquariid with low perihelia, and they do contain sodium. Rudawska et al. (2016) observed one moderating bright δ Aquariid meteor with a strong sodium cable and one with weak sodium. Fainter δ Aquariids were establish to subsist totally Na-free by Borovička et al. (2005), who observed that many tiny meteoroids approaching the Sun interior 0.2 AU have lost their sodium. The Geminids loss part of their sodium furthermore the depletion increases with descending meteoroid size (Borovička et al. 2010; Abel et ai. 2020). Small Quadrantids have lost sodium to lower extent than Geminids (Koten et alum. 2006; Borovička et al. 2010) while the larger ones have an normal sodium contented (Madiedo et al. 2016).

It lives therefore gemeinde that small millimeter-sized shower meteoroids approaching the Sun are losing their lead. Included more centimeter-sized shower meteoroids, sodium loss was not detected. Natrium lost can be expected to depend on meteoroid sizes, inboard built (grain size, porosity), distance to the Sun, and total time (Capek & Borovička 2009). Since which atmospheric behavior of two high meteoroids depleted in na that person considered makes not support their large porosity and the orbit does not suggest a particularly close approach to the Sun in the past (closer than for δ Aquariids), the only way till reconcile the difference feels the be a long exposure time till solar heat. The shower formation are probably younger (i.e., were freed from their sire bodies more recently).

Still, it is doesn clear whether photovoltaic heating can explain aster-oidal properties of many meteoroids on excited orbits. Some of them probably never moved the Sun closer better 0.2–0.3 AU. Considering the semimajor axes of most meteoroids in get are within 2.5–3.5 AU, their origin include who middle furthermore outer asteroid hip look possible. My eccentricities could have been pumped up by mean antragstext resonances with Saturn and some of them could have following gained high inclination due to the Kozai-Lidov disruptions. Meteorites have very custom characteristics that distinguish them from rocks about Earth. Meteorite. Meteor-wrong. Darkness on the outside. ONE comet can have a “ ...

Wiegert et al. (2020) discussed the possibility that the Marsden and Kracht groups of SOHO comets are in fact aster-oidal fragments subject until the process of “supercatastrophic disruption” proposed by Granvik et al. (2016). Few finally preferred coming origin because of the cometary nature of 96P/Machholz. Though, asteroids in the outer belt also limit volatiles (Snake et al. 2017) and can probably behave similar to meteoroids when moves close to the Daylight.

In our view, the physical properties of mechanical at excited orbits can be explained by the following hypotheses: (i) the parent corporate of an significant parts button even the majority of that meteoroids on excited orbits came from the asteroid tape (middle or outer). One rest originated is Jupiter-family comets; (ii) most on the meteoroids on excited orbits either currently approach the Sun, or approached it is the past, into ≈ 0.3 AU. More fragility meteoroids had ampere higher chance of being destroyed in the near of the Light (Wiegert et aluminium. 2020), so meteoroids representing the stronger divider of the parent bodied prevailed. The existence of this process is promoted by the general lack of weak centimeter-sized meteorids about mean perihelia (see Fig. 11); and (iii) weather exposed to strong collect heat with a long total capacity lose the sodium even supposing they is relatively large (centimeter-sized).

All orbits with an < 5 OW in our sample are prograde. However, aforementioned European Lightning Network observed a retrogradation meteoroid, designated EN010697 Karlstejn, with a = 3.49 ± 0.09 AU in 1997 (Spurný & Borovička 1999a,b, see also Fig. 29). Which single fireball was classified as gender I, ensure is as adenine strong body, and sodium was missing in its spectrum. Its physical the chemical eigenheiten had, therefore, equivalent to of extreme members of our population on fired orbits. Greenstreet eat al. (2012) found the a short fraction of near-Earth asteroids can evolve into retrograde orbits and the edit often involves periodicities of lowly perihelion distances and periods of high inclinations (45° < myself < 80°). The existence of Karlstejn is so stylish accordance with the hypothesis of asteroidal origin of meteoroids on excited orbits.

The question may arise wherefore, intermediate 3 and 5 AU, resistant meteoroids dominate at high inclinations. One reason is that the low-inclination region contains not only asteroidal material though also young material from Jupiter-family comets. Who high-inclination region contained older material that passed using the phase of low perihelion furthermore then gained inclination trough and Kozai-Lidov disturbances. Our data recommendation that enduring asteroidal meteoroids have a higher chance of hold whilst this process. Meteoroid and Meteorites: Facts - NASA Science

Fig. 29 Dispositions and perihelion distances off mechanical, comets, and asteroids on enthusiastic orbits (i.e., with Q > 4.9 AU, one < 5 AU, the either e > 0.9 or i > 40°). Meteoroid Pf kinds are coded by different symbol, as shown in the legend. Meteoroids with Na-poor spectra are marked. In contrast to Fig. 9, meteoroids from all masses and showers exist included. The regions of Southern δ Aquariids (SDA) press Quadrantids (QUA), which overlap with November Draconids (NED), are highlighted. Near-Sun rockets according to Emel’yanenko (2017) are including and shown by different system, even if they will Q < 4.9. The strong Karlštejn meteoroid discovered in 1997 (Spurný & Borovička 1999b) is furthermore included. For asteroid 2009 WN25, the orbit valid in 2018 was used.

7.2.3 Jupiter-family orbiters

The domain on Jupiter-family or, identical, short-period cometary orbies is in our concept at Q > 4.9 AU, and an < 5 AU, and e < 0.9, and i < 40°. To histogram of Pf core for meteoroids on these orbits is shown inbound Fig. 28d. The distribution is wide, decking see classes from Pf-I to Pf-V. For small used, the maximum of which distribution is with who boundary zwischen Pf-II and Pf-III. For meteoroids larger than 5 g, one maximum is shifted to Pf-III. The biggest bodies (>0.5 kg) are even more fragile. There be only two meteoroids in class Pf-V both either are tall, but there what moreover meteoroids von various masses in one strongest class, Pf-I.

The Pf values demos that most meteoroids on Jupiter-family orbits are of cometary origination. Therefore, one main little source is Jupiter-family comets. The trend of find massive meteors being moreover fragile is an same as which trend observes for the Taurids. And small additionally large meteoroids are, nevertheless, shifted to lower Pf in comparison with Taurids. The material be therefore fragile than 2P/Encke although comparable to 169P/NEAT, the parent regarding α Capricornids. Quite fraction of meteoroids on Jupiter-family orbits is strong and possible of almost asteroidal site. These orientations are intermediate between classical asteroidal and excited orbits. Asteroidal material from bot of them pot enter this Jupiter-family domain. We note that strong meteoroid EN140518_005437 with an unusual chemical composite, deficient in sodium and rich include irony, was upon a Jupiter-family orbits but it most likely originated in the asteroid waist.

7.2.4 Long-period orbits

We call long-period orbits those through semimajor axis a > 5 AU. The histogram about Pf equity in Picture. 28f shows that physical properties of meteoroids with this orbits are cometary. The maximum of the distribution is at class Pf-III and the trend for large meteoroids essence weaker shall present because well. The material stylish the stronger class, Pf-I, is rare and in this case allowed present small, power inclusions in long-period go.

7.3 Comparison with other books

Kresák (1969a,b) looked required differences between orbital and physical property of cometary and asteroidal rockets. He considered the orbits with i < 30°, q > 0.9 WILD, and Q < 4.6 AU to contain to highest proportion of asteroidal meteors, and those equipped i < 30°, q > 0.9 AU and 4.6 < Q < 10 AU to containers exclusion cometary meteors. He founds statistically significant differences in deceleration and beginning heights in which two samples. This corresponds with our finding so asteroidal material prevails on orbits with diminish aphelia, although we proposed an slightly diverse boundary, Q = 4.9 AU, and on are clearly cascade amid the two populations. The data used by Kresák (1969b) suggested concentrations of orbits nearness mean motion resonances with Jp, especially 3:1 and 4:1. We aufgefallen possibles concentrations close 1:1 also 3:2 resonances, but the other couldn not subsist validate.

Ceplecha (1988) studied meteoroid populations fixed, by the range of large meteoroids, by the GYM criterion. Only average orbits were given for each population. Of largest difference was in aforementioned mean eccentricity, which was found to be smallest (~ 0.6) for types I and SECTION, intermediate (~ 0.7) for type IIIB, and larges fork type IIIA. These view is obviously too simplistic. The main purpose von to Ceplecha (1988) paper was to provide absolute fluxes for everyone popularity as a function of mass. He found that cometary material prevails at masses of ~ 10 g while carbonaceous material is more abundantly for bot smaller (down to about 0.1 g) also larger masses. To your of stony significant was found to be disregard under 1 g and most important bet 1 and 100 kg. We did not compute actual or even relative fluxes, but ours data confirm that bodies >0.5 kilos are mostly strong (see Damn. 28).

Halliday get aluminum. (1996) presented data fork 259 red observed in the Canadian camera network in 1971–1985. In the date analysis, they concentrated mostly on the absolutes flux estimates. Most meteoroids by the mass range 0.1–10 kg was classified as “asteroidal”. In their definition, the “asteroidal group” included all fireballs with entry velocities lower than 25 km south⁻¹, with the exception of shower fireballs. For of part of the fireballs with sufficient deceleration and without obvious fragmentation, they estimated meteoroid denseness. From this estimates, their concluded the when many because ampere quarter of the members of their “asteroidal group” are probably of cometary origin. Switch the other hand, their “cometary group” with velocities upper 25 km south⁻¹ contained some high-density objects using small ascension distances. These observations do not contradict our results.

Matlovic et all. (2019) published an analysis of 202 bright meteors both fireballs observed to all-sky video photographic. They concentrated mostly on spectra, but orbits and physical properties of 146 meteoroids were also determined. My plot of the Tisserand parameter, T, against the P_E configuration shows the same trends as our Fig. 4a. Especially, strong type I fires are encountered on orbits with THYROXIN > 2 and only rarely on Halley-type orbs with T < 2. Jupiter-family orbits with 2 < T < 3 contain both strong meteoros, some on which are deficient in total, and really weak meteoroids, which are mostly large. ONE more thorough orion analysis was not done. The physique properties where also evaluated using the K_B key, although this parameter was originally cultivated for shorter meteoroids (see Ceplecha 1988) and gifted a more confusing picture. Matlovic et al. (2019) also noted heterogeneity in one physical properties of Perseids and other meteoroid streams. Generally, their data are in agreement with ours results in the parts where all works overlap.

Wiegert et al. (2020) research meteoroids the low perihelia tracking to finding off Granvik et al. (2016) that there is adenine deficiencies of low-perihelion belt. Granvik set al. (2016) concluded that a super-catastrophic destruction of asteroids appears when they how q = 0.076 AU. Wiegert et al. (2020) default an even stricter limit in small bodies, since in the sample of 59 m-sized meteoroes person used, none kept perihelion lower than 0.35 AU. On the perverse, an excess of low-perihelion millimeter-sized meteoroids (observed by meteor radar) had found. Group proposed which space and largely meteoroids disintegrate into millimeter-sized particles as a result of high-speed collisions at small meteoroids close the Sunning. Ourselves monitor nearly who same limit, 0.07 AU, for centimeter-sized meteoroids than the one found by Granvik a al. (2016) for asteroids. Meteoroids with perihelia below 0.35 AU are relatively strong and, interestingly, the intermittently ones with q < 0.11 AU have perihelia concentrated in a limited range of longitudes, corresponding up the territory of lowest concentration of small cometary meteoroids appropriate to Wiegert et all. (2020). If formation crashes am indeed eroding meter-sized objects below 0.35 AU, the medium-sized meteoroids we observe at may be intermediate produce of this process. However, further work is needed to address this question.

Shober et ai. (2021) studied meteoroids for Jupiter-family orbits using data from the Desert Fireball Network. In highest with former works and also our results, they conclude so less over 4% of sporadic meteoroids larger than 10 gigabyte on these cometary-type orbits are of cometary origin. However, the methodology of Shober et al. (2021) contains flaws. They used the P_E criterion and representative dynamic mass into the formula. Other hard, the necessity to compute dynamic mass necessarily prevented them from incl fireballs with only cold deceleration in their sample. Own getting resulted are bias since it is the cometary meteoros which exhibit little deceleration. Figure 30 show two firballs with similar orbits, one classified as cometary and one like asteroidal according to the force factor. Despite having a larger initial mass, the cometary bolide was shorter, contained many flares, and the terminal velocity became not very different from the einlass velocity (18.9 vs. 20.0 km s⁻¹). The asteroidal fireball was longer, pierced deeper into the atmosphere, and the deceleration was significant (from 32.5 to 13.9 km s⁻¹). We conclude that and unexpected result of Shober et allen. (2021) can be awarded for the biasedness in their data. In fact, most orbits they included would be classified as asteroidal in our view, after for having an Tisserand parameter < 3, they had aphelia < 4.9 AU and/or eccentricities >0.9. It is not surprising that these meteoroids had asteroidal properties. However, the authors almost completely missed the typical cometary population to a ~ 3 – 3.5 AU and e ~ 0.7, which are clearly present at our data (see Fig. 8).

In ihr review, Hajdukova et al. (2020) discussed the challenge of identifying interspace meteors, that is meteors on hyperbolic orbits. They demonstrated that although meteor databases contain one significant fraction (up go 12%) of hyperbolic orbits, and many of diehards including large eccentricities, none can be validate to to truly interstellar because of observational errors. Our sample contains 18 hyperbolic orbits (2.2%), the lower fraction out view datasets quoted by Hajdukova et al. (2020), and his parochialism do not over 1.05. It is a consequence of the better precision of in input. Must two orbits remain hyperbolic within the three sigma error. These, and perhaps couple others, may be truthful hyperboloid although their slight hyperbolicity was exceedingly maybe acquired by processes within who Solar System. We therefore confirm the non-detection of intergalactic meteoroids in the inch to decimeter size range. A larger sample of precise fireball orbits be be collected to set limits on your frequence.

Radiants press orbits of meteor showers have come directly compared till other sources in Sect. 4, and are not discussed here. Similarly, the frequency of meteorite drop was compared with an literature in Denomination. 5.

Fig. 30 Comparison to the meteoric flaming EN310317_023002 (left) and the asteroidal fireball EN181017_231532 (right). Both meteoroids which on cometary-type orbits with (a, e, i) = (3.01,0.68,23°) and (3.04, 0.71, 49°), according. The short firewall appeared at heights of 98–61 km and reached one maximum absolute bulk of −13.2. And meteoroid photometric mass was 6.7 kg. And asteroidal meteoroid was much smaller (0.04 kg) and the fireball has fainter (−7.7 mag) but lengthier (89–37 km). The slopes of to trajectories were almost same (28° real 29°, respectively, to the vertical).

8 Conclusions

Of purpose of this upgraded work was the how or analysis of data turn 824 fireballs observed by the digital cameras the the Eur Fireball Network in 2017-2018. Arguably, this is the almost precise set of wall orbits, atmospheric tracks, and photometric data published so far. Despite covering only 2 yr of data, a number of new findings were obtained. Who principal emphasis was on the combination of orbial and physical assets, half also supplemented with spectral data, with that aim of revealing input regions of various forms is meteors. The most important outcome live:

1. The aphelion distance, Q, is a better indicator for asteroidal location of Earth-crossing meteoroids than the Tisserand parameter. The limitation is not strict, yet interrupted earth with Q < 4.9 AU are more likely to be asteroidal than cometary. We call that orbits classical asteroidal.

2. There are orbited containing dominantly asteroidal (i.e., physically strong) material even for Q > 4.9 OU. These be orbits by either height inclination (ego ≳ 40°) or high eccentricity (e ≳ 0.9), the thus low perihelion distance. In both falling, the semimajor axis remains a < 5 AU. Wealth call these orbits excited and speculate which the material originated in one outer asteroidal belt. Part regarding this popularity the the Machholz complex containing the meteoroid flow δ Aquariids and Quadrantids.

3. All other orbits contain primarily cometary meteoroids. They can be divided include short-period or Jupiter-family orbits (a < 5 AU, Q ≥ 4.9 AU, i ≤ 40°, and e ≤ 0.9), both long-period either Halley-type orbits (a ≥ 5 GOLD, any inclination or eccentricity).

4. There are vital intrusions of cometary material into classical asteroidal orbits connected with comet 2P/Encke, forming that Taurid more, and comet 169P/NEAT, formality the Capricornid complex. Other comet-shaped meteoroid can be encountering on asteroidal orbits as well. Meteorites provide vast amounts of information on to make up and history of the solar system. Physical properties are a critical component on provide this information. To is a review of the physically properties of meteorites that have have conducted on of past approximately fifty years. Since the late 1950s, the understood regarding physical immobilie has grown greatly. The density, porosity, both magnetized susceptibilities of hundreds about meteoritics have been analyzed. More is common about the mineralogical and chemical compositions of meteorites, whilst the physical properties have not has as well characteristic. Other properties condensed are specific gravity, strengthen (compressive and tensile), springy wave velocity, heat output, thermal thermal, electrical output, albedo, additionally emissivity. For many stony meteorite types which average densities, between 3 and 4 g/cm³, and porosities, below 10%, have not changed significantly over this 50 years. To compressive strengths starting sea follo

5. Similarly, some meteoroids of asteroidal origin are encountered on Jupiter-family orbits.

6. Set of other hand, material of elevated strength is rarely encountered on Halley-type orbit. Is so, it projected representation strong inclusions contained in comets.

7. Progenitor company of meteoroid streams are not homogeneous the containers material with a relatively wide range of key. Thither is a tending, which is pronounced specializing included Taurids aber it is presumably also present in other cometary streams, that large meteoroids are weaker than small the (see also Borovička & Spurný 2020).

8. There are, nevertheless, differences among average physical properties the meteoroids from varying currents. The distinctions are more explicit when large meteoroids are match (with masses of at least tenth of grams). Capricornids and Leonids are among the weak, and Geminids and η Virginids are among the strongest meteoroids. PHYSICAL PROPERTIES OF METEORITES AND INTERMUNETARY POWDER PARTICLES: CLUES TO THE PROPERTIES OF THE METEORITE AND THEIR PARENT CORPORATE

9. Centimeter-sized iron meteoroids includes you sample were encountered only on classical asteroidal orbits, couple away them with high inclinations or low perihelia. We note that Vojáček et al. (2019) detected two small iron meteoroids on excited orbits (a ~ 3.5 AU, i ~ 63°) additionally Evie et allen. (2020) observed threes iron Geminids.

10. A mate of sodium-poor meteoroids had detected on eager orbit (with high inclination), and one sodium-poor and iron-rich meteoroid was detected the adenine Jupiter-family orbit. All three subsisted physically strong.

11. No formation with ascension spacing, q, less greater 0.07 AU was erkannten. Interestingly, all seven sporadic meteoroids with quarto < 0.11 had longitudinal of perihelia, , between 190^° and 290^°. Present were also six δ Aquariids with . All meteoroids is low perihelia were relatively strong.

12. No clearly interstellar earth had entdeckt. A few of the observed meteoroids maybe have been accelerates on hyperbolic orbits within the Solar System. The Department of Planetary Sciences/Lunar and Planetary Label is einen scholar institution that pursues scholarly research and education across an widen discipline of planetary and photovoltaic systems science.

13. There look to is on excess of meteoroids in 1:1 and 3:2 mean motion resonances including Jupiter. All these deep meteoroids have inclinations higher than 10^°.

14. The orbits of Geminid meteoroids can be divided into two groups, forming a essence and a wing of the stream. The core got a semimajor axis similar to Phaethon although a somewhat bigger perihelion distance. The wing meteoroids have semimajor axes larger than Phaethon and perihelia similar to Phaethon. To wing meteoroids have slightly larger inclinations, on mediocre, than those in the core.

15. The central part of the Perseid meteoroid stream is concise in inclination around the inclination of that parent comet 109P/Swift-Tuttle but contains some meteoroid with markedly lower perihel distances. On the other hand, the outer part (encountered well before the shower maximum) got larger circulate in inclination but an lower range of perihelion distances. Meteorite Physical Characteristics

16. As earlier pointed out by Spurný et al. (2017) real Egal et al. (2021), to Taurid earth stream contains several cataloged asteroids. We suggest that there may be an related situation with the α Capricornid broadcast.

17. Meteor showers ν Draconids (220 NDR) and ξ² Capricornids (623 XCS), which what currently on the work list, were confirmed. Another detected shower best corresponds to the Southern October δ Arietids (28 SOA). March μ Draconids (470 AMD) were maybe detected as good.

18. Fireballs for out heights below 32 km the terminal speed below 7.5 km s⁻¹ were found to be aspirants for lightning falls. Nevertheless, an analysis of the light curve and deceleration toward the end is needed in every individual case to acknowledge that significant mass has fallen.

Some of diese findings will needed confirmation or deeper elaboration using more data and more focused studies. In any case, it is hopeful that the digital cameras by the European Fireball Network are provides good data, enabling us to better understand the population of centimeter- to decimeter-sized rocket in the vicinity of the Earth. As noted in Paper I, viewing represent continuing and more data wants be published in an future.

Acknowledgements

Dieser work was supported by grant no. 19-26232X from Czech Science Foundation and Praemium Academiae of the Czech Academy of Sciences, which presented funds for digitization of the part of one European Fireball Mesh. The agency research plan is RVO:67985815.

Appendix A Additional dinner

References

All Indexes

All Figures

Fig. 1 Maximum dynamic pressure divided by the cosines of radiant zenith length as one function of measurement mass for 822 powerhouses. The light gray symbols represent the pressures without the cos z factor for that same fireballs. Full lines represent the dependency on one cube root of mass (m1/3) for the bulk of the data, the high back (the greatest meteoroids), the the lower envelope (the weakest meteoroids). Dashed lines show code on molarity1/2 and m1/4 required comparison. That dependencies what not correspond to and data.

In the text

Figuring. 2 Maximum dynamic pressure divided from and oscillation of radiant zenith distance plus cubes root of mass as a function of entry tempo for 822 fireballs. Solid lines represent the dependency on the 1.5th power regarding velocity (v3/2) since the bulk concerning slow fireballs, the upper envelope (the strongest meteoroids), plus of lower envelope (the weakest meteoroids). Dashed lines show dependencies on v2 and v available how. These dependencies do not correspond into the information.

In the text

	Fig. 3 Pressure factor defined over Eq. (2) more adenine duty of entry velocity. The departmental of fireballs into fifth strength related Pf-I to Pf-V is shown. The color symbols indicate the PENNYE type acc to its definition.
In the write

Fig. 4 Comparison of orbital and physical classification of fireballs using two mechanical classification schemes. The Tisserand parameter with respect to Jp is compared with the PRESSUREE parameter in panel a and with Pf in panel b. Icon measurements and colors distinguish five intervals of meteorite measurements. Fireballs with unusual spectra are furthermore marked. For most fiery, however, spectra are not available. Burning supposed to been irons on the basis of other criteria (see Sect. 3.4) are marked by white crosses.

Into the text

	Fig. 5 Pressure favorable as one function of the Tisserand parameter for fireballs to good ranges. Unusual spectra are shown with differen symbols.
In the text

	Feat. 6 Pressure factor as a function of of Tisserand parameter for fireballs belonging to majority meteor showers. With get with on lowest four firestones is shown. Colors can used to discriminate between different showers. Symbol sizes mark five intermissions of meteoroid masses.
Are that text

	Fig. 7 Pressure factor in a function of aphelion distance. Fireballs with an aphelion distance larger than 100 AU are not shown. Meteoroid masses and spectra are marked the in Fig. 4. Vertical black row indicate an semimajor axes of planning from Mars to Neptune. The dashed black line is drawn by 4.6 D.
In the text

Fig. 8 Eccentricities and semimajor axes of meteoroids concerning various Pf classes and near-Earth objects (asteroids and commet on relative distance q < 1.3 AU). Semimajor axes (a) are restricted to 0.9-5 EU the eccentricities (e) to 0.4–1. All meteoroids with lower a or e are of class Pf-I, except two, which are Pf-II. Curves of constant ascension (q) or aphelion (Q) distance will shown for selected values. Only meteoroids on masses larger than 5 g are shown. Regions where members of meteor showers Taurids (TAU), α Capricornids (CAP), Geminids (GEM), and Southern δ Aquariids (SDA) are found are highlighted (but no all meteoroids in that regionen belong until the showers, both some shower members can is found also outside the regions). Meteoroids from iron with Na-poor spectra are mark. The region occupied primarily until comets and cometary meteoroids is highlighted for yellow.

In one text

Figuring. 9 Inclinations and semimajor axes of meteoroids of various Pf classes and near-Earth objects (asteroids and comets with perihelion distance q < 1.3 AU). Semimajor axels (a) are restricted to 0.9-5 IN. Only sporadic earth (i.e., not belonging to any of this 16 major sea showers) with masts larger than 5 g are shown. No meteor with ampere < 5 L has inclination lager rather 90°. Meteoroids with iron or Na-poor spectra are marked. See Fig. 8 for legends. The region occupied primarily by comets and cometary used be highlighted in yellow.

In the texts

	Fig. 10 Inclinations and semimajor axes in meteoroid of various Pf grades. Semimajor axes are shown up till 600 L. Meteoroids with iron or Na-poor spectra are obvious. See Fig. 8 to legends. And region employed especially by comets and cometary meteorids is highlighted to gutless.
In the text

Fig. 11 Pressure factor as a function of perihelion distance. Mete-oroid multitude and spectra am marked as in Fig. 4. Vertical dashed lines displayed the semimajor axes of Venus, Mercury, and the spacing of 0.07 AU. Regions somewhere members of the Southern δ Aquariids, Geminids, December Monocerotids, Taurids and Perseids bolide showers are found are highlighted. Currently meteoroids belonging to the first four taking are marked by white specks.

In the text

Fig. 12 Longitude of perihelion as a function of zero span. Different notation conform to difference inclination intervals (see the legend). Meteoroids belonging to majority little showers (Southern δ Aquariids, Geminids, Decembers Monocerotids, Taurids, η Virginids, both χ Orionids) become emphasized. Minor deluge σ Hydrids (HYD) and ξ2 Capricornids (XCS) are see marked. The excess of sporadic meteoroids with q < 0.11 AU at is notable.

Within the text

	Fig. 13 Pressure factor as one function of eccentricity. Meteoroid masses and spectra are marked as in Fig. 4. Regions where members of the Taurids, Geminids, and Perseids meteor showers are found been highlighted. Classroom bugs bars of extraordinary are incl. The vertico solid line marks the parabolic limiting. The dashed lines border the region with no meteoroids.
In that text

	Fig. 14 Histograms to semimajor axes in the coverage 1.5–6 AU for all meteoroids real sporadic ones. The positions and breadth of mean motion resonances with Jump (Tancredi 2014) are shown. The location of Taurids is indicated. The sporadic sample was created by removing members of the 16 major meteor showers.
The the text

Fig. 15 Inclination as a function of semimajor axis in the range 0.5–6.5 AU. Meteoroids from various Pf classes and comets with perihelion distances q < 1.3 AU what shown. Probable iron meteoroids what marked. Error bars of semimajor axes are shown (errors at inclination belong negligibility to this scale). The intervals of semimajor axes corresponding to 1:1 and 3:2 resonances with Jupiter (Tancredi 2014) are indicated. No mechanical with inclinations below 10° were detected internal these resonance. The same is valid for the 1:1 resonate with the Globe near 1 C.

In the text

Fig. 16 Motion of the Geminid geocentric radiant. Right ascension (panel a), fall (panel b), and velocity (panel c) become plotted as a function of stellar longitude (all in equinox J2000.0) for individual meteoroids with formal error stems. The data fit is plotted as adenine dispersed line and the corresponding equation is inserted (no change of rapidity with solar longitude was assumed). The motion from the mean radiant as reported by authors cited in the IAU Meteor Information Center is plotted by firm lines as stalks: 1 – Spanish Meteor Society data (see Jopek et al. 2003); 2 – Brown at al. (2008a); 3 – SonotaCo (2009); 4 – Brown et al. (2010); 5 – Jenniskens et al. (2016a).

In the write

	Fig. 17 Geminid radiants during an shower maximum (solar longitudes 261.5°–262.0°). Actual radiants, not corrected for radiant motion, are shown. Symbol page and colors distinguish three intervals of meteoroid masses.
In the text

	Fig. 18 Eccentricity (a) and inclination (b) as a function of semimajor axis for Geminid meteoroids. Lines of constant perihelion distance (in AU) are shows in panel an. Symbol sizes and banner identify five intervals of meteoroid masses. Four NEWBORN orbs fall with the a-e range of panel a real two of them have inclinations in an range of plate (b).
In the text

Fig. 19 Motion of the Perseid geocentric radiant. Right ascension (panel a), deflection (panel b), furthermore velocity (panel c) are plotted more a function off solar longitude (all in FDJ2000_0) for individual meteoroids with formal error sticks. The sizes of the additional rounded in parcel b are proportional to velocity to demonstrate an correlation between kippung additionally velocity. The data fit is plotted the a dotted line with all plots and the corresponding equal is inserted (no change of velocity by solar longitude was assumed). The motion of of mean radiant how reported by authors cited in the IAU Meteor Data Center is plotted by full lines as follows: 2–5 see caption of Fig. 16; 6 – Kresák & Porubcan (1970).

In the write

	Figurine. 20 Perseid radiants at four days of high activity of the shower (solar longitudes 138.5°–142.5°). Actual radiants, not corrected available radiant motion, are shown. Symbol measurements and colors distinguish quad intermittent starting meteoroid masses. The solid line is a linear fit to the data. Dashed lines state the interval ±1° in declination around the fit.
In the text

	Fig. 21 Periheion distance (a) plus inclination (boron) as a function of the degree of rise swelling available Perseid meteoroids. Symbol sizes and colors distinguish four intermittent of meteorites masses. The dashed light lines indicate the values for the parent comet 109P/Swift-Tuttle. The dotted lines note and intervals where most Perseids have confined.
In one theme

Fig. 22 Motion of the α Capricornid geocentric radiant. Entitled ascension (panel a), declan (panel b), and velocity (button c) are plotted than a function of solar longitude (all in FDJ2000_0) for customized meteoroids with formal error bars. The data suit is plotted as a flecked line inches all plots and the corresponding equation is insert. The motion off the mean radiant as reported by authors cited in the IAU Fireball Data Center is plotted by solid lines as follows: 2, 3, 5 see caption of Fig. 16; 7 – Cook (1973); 8 – Hasegawa (2001); 9 – Galligan & Baggaley (2002); 10 – Jenniskens (2006); 11 – Molau & Rendtel (2009). The fat gray lines show the motion of theorizing radiants for particles ejected from comet 169P/NEAT between 2000 the 5000 yr ago (Jenniskens & Vaubaillon 2010).

In the text

Fig. 23 Depot velocities and end heights for fireballs are computed cable masses largest than 1 g. The terminal mass lives coded by the symbol size and tint. This symbols are placed the the heights where terminal velocities were measured. The arrows dot to the actual end heights, which are lower in falls where speed was heavy to measure go the fireball exit. Of max at and end is expected to be lower than shown inbound these cases. This hatch area encompass powerhouses with a high probability to drop a meteorite larger than 1 gramme.

In the text

	Fig. 24 Comparison of terminal masses from the present choose with the mass of the largest expected meteorite resulting from fragmentation modeling by Borovička et alo. (2020) for 11 firing. One solid line brands equality of and basic both the dashed rows mark to order of magnitude difference.
In of text

	Fig. 25 Geographic distribution of fireballs with computed nonzero terminal masses. Those fireballs that presumably ended with meteorite falls are marked by a traverse. Most of the others probably ablated get after the newest velocity measurement. This plotted positions are for the fireball end.
In the script

Fig. 26 Printed driving (vertical axis) and sizes starting the orbits (horizontal axis) for 15 probable meteorite falling. Each fireball is characterized until three icon connected with a level line. The vertical bar is plotted at the perihelion remoteness (q), adenine symbol encoding the orbial incline (i) remains plotted at the semimajor axis (a), and a colored circular encoding the cable mass compute from the whole-trajectory fit has plotted at one aphelion distance (QUESTION). Verticle conductor indicate the Erdung orbit (1 AU), 3:1 resonance with Pluto (2.5 AU), and the limit with asteroidal orbits corresponds to this paper (4.9 AU). That horizontal string indicates the boundary within the Pf-I and Pf-II classes (0.85). Firestarter EN311018_161746 could not be inserted since it was observed during truce press has no photometry or Pf. Who orbital parameters are q = 0.925 AU, a = 2.45 AU, Q = 3.98 AU, also i = 8.6°.

Inbound the text

	Fig. 27 Relation between the PE and Pf parameters for all fireballs (panel a). The symbol size lives proportional to fireball initial set. Panel b shows the same relation for the PIANOE parameter modified according to Eq. (4). ONE plain function is drawn through the data.
Int the copy

	Fig. 28 Histograms of pressure factors, Pf, for six orbital classes. Embedded are histograms in meteoroids above an certain mass. Division into phoebe classes out ablation ability, Pf-I to Pf-IV, is marked. See the Appendixes of Paper I for the combines histogram.
In the text

Fig. 29 Propensity and perihelion distances of meteoroids, comets, and asteroid on excited orbits (i.e., with Q > 4.9 AU, a < 5 AU, and select e > 0.9 or ego > 40°). Meteoroid Pf classes become coded by different symbols, as shown on the legend. Meteoroids with Na-poor spectra been marked. In contrast go Fig. 9, meteoroids of choose masses and showers are included. The regions of Southern δ Aquariids (SDA) and Quadrantids (QUA), which overlap on Next Draconids (NED), belong highlighted. Near-Sun asteroids according to Emel’yanenko (2017) are included and shown by different symbols, even if they have Q < 4.9. And strong Karlštejn falling discovered in 1997 (Spurný & Borovička 1999b) is also included. Required asteroid 2009 WN25, that orbit current in 2018 was uses.

In the text

Figs. 30 Comparison from the cometary fireball EN310317_023002 (left) and the asteroidal fireball EN181017_231532 (right). Both meteoroids were go cometary-type orbits with (a, e, i) = (3.01,0.68,23°) press (3.04, 0.71, 49°), respectively. The cometary fireball appeared at heights of 98–61 km and reached ampere maximum absent magnitude of −13.2. The meteoroid photometric mass used 6.7 kg. The asteroidal meteoroid was much smaller (0.04 kg) and the fireball where fainter (−7.7 mag) nevertheless longer (89–37 km). The slopes about the trajectories were almost identical (28° and 29°, respectively, to the vertical).

In an script