Asteroid family

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Asteroid families become visible as distinct concentrations when asteroids are plotted in the proper orbital element space (ip vs ap). Some prominent families are the Vesta, Eunomia, Koronis, Eos, and Themis family located in different (colorized) regions of the asteroid belt. AsteroidIncAu.png
Asteroid families become visible as distinct concentrations when asteroids are plotted in the proper orbital element space (i p vs a p). Some prominent families are the Vesta, Eunomia, Koronis, Eos, and Themis family located in different (colorized) regions of the asteroid belt.

An asteroid family is a population of asteroids that share similar proper orbital elements, such as semimajor axis, eccentricity, and orbital inclination. The members of the families are thought to be fragments of past asteroid collisions. An asteroid family is a more specific term than asteroid group whose members, while sharing some broad orbital characteristics, may be otherwise unrelated to each other.

Contents

General properties

Plot of proper inclination vs. eccentricity for numbered asteroids Asteroid proper elements i vs e.png
Plot of proper inclination vs. eccentricity for numbered asteroids

Large prominent families contain several hundred recognized asteroids (and many more smaller objects which may be either not-yet-analyzed, or not-yet-discovered). Small, compact families may have only about ten identified members. About 33% to 35% of asteroids in the main belt are family members.

There are about 20 to 30 reliably recognized families, with several tens of less certain groupings. Most asteroid families are found in the main asteroid belt, although several family-like groups such as the Pallas family, Hungaria family, and the Phocaea family lie at smaller semi-major axis or larger inclination than the main belt.

One family has been identified associated with the dwarf planet Haumea. [1] Some studies have tried to find evidence of collisional families among the trojan asteroids, but at present the evidence is inconclusive.

Origin and evolution

The families are thought to form as a result of collisions between asteroids. In many or most cases the parent body was shattered, but there are also several families which resulted from a large cratering event which did not disrupt the parent body (e.g. the Vesta, Pallas, Hygiea, and Massalia families). Such cratering families typically consist of a single large body and a swarm of asteroids that are much smaller. Some families (e.g. the Flora family) have complex internal structures which are not satisfactorily explained at the moment, but may be due to several collisions in the same region at different times.

Due to the method of origin, all the members have closely matching compositions for most families. Notable exceptions are those families (such as the Vesta family) which formed from a large differentiated parent body.

Asteroid families are thought to have lifetimes of the order of a billion years, depending on various factors (e.g. smaller asteroids are lost faster). This is significantly shorter than the Solar System's age, so few if any are relics of the early Solar System. Decay of families occurs both because of slow dissipation of the orbits due to perturbations from Jupiter or other large bodies, and because of collisions between asteroids which grind them down to small bodies. Such small asteroids then become subject to perturbations such as the Yarkovsky effect that can push them towards orbital resonances with Jupiter over time. Once there, they are relatively rapidly ejected from the asteroid belt. Tentative age estimates have been obtained for some families, ranging from hundreds of millions of years to less than several million years as for the compact Karin family. Old families are thought to contain few small members, and this is the basis of the age determinations.

It is supposed that many very old families have lost all the smaller and medium-sized members, leaving only a few of the largest intact. A suggested example of such old family remains are the 9 Metis and 113 Amalthea pair. Further evidence for a large number of past families (now dispersed) comes from analysis of chemical ratios in iron meteorites. These show that there must have once been at least 50 to 100 parent bodies large enough to be differentiated, that have since been shattered to expose their cores and produce the actual meteorites (Kelley & Gaffey 2000).

Identification of members, interlopers and background asteroids

When the orbital elements of main belt asteroids are plotted (typically inclination vs. eccentricity, or vs. semi-major axis), a number of distinct concentrations are seen against the rather uniform distribution of non-family background asteroids. These concentrations are the asteroid families (see above). Interlopers are asteroids classified as family members based on their so-called proper orbital elements but having spectroscopic properties distinct from the bulk of the family, suggesting that they, contrary to the true family members, did not originate from the same parent body that once fragmented upon a collisional impact.

Description

Comparison: osculating Keplerian orbital elements on the left (families indistinguishable) vs. proper elements on the right (families visible). Asteroid osculating vs proper elements.png
Comparison: osculating Keplerian orbital elements on the left (families indistinguishable) vs. proper elements on the right (families visible).

Strictly speaking, families and their membership are identified by analysing the proper orbital elements rather than the current osculating orbital elements, which regularly fluctuate on timescales of tens of thousands of years. The proper elements are related constants of motion that remain almost constant for at least tens of millions of years, and perhaps longer.

The Japanese astronomer Kiyotsugu Hirayama (1874–1943) pioneered the estimation of proper elements for asteroids, and first identified several of the most prominent families in 1918. In his honor, asteroid families are sometimes called Hirayama families. This particularly applies to the five prominent groupings discovered by him.

Hierarchical clustering method

Present day computer-assisted searches have identified more than a hundred asteroid families. The most prominent algorithms have been the hierarchical clustering method (HCM), which looks for groupings with small nearest-neighbour distances in orbital element space, and wavelet analysis, which builds a density-of-asteroids map in orbital element space, and looks for density peaks.

The boundaries of the families are somewhat vague because at the edges they blend into the background density of asteroids in the main belt. For this reason the number of members even among discovered asteroids is usually only known approximately, and membership is uncertain for asteroids near the edges.

Additionally, some interlopers from the heterogeneous background asteroid population are expected even in the central regions of a family. Since the true family members caused by the collision are expected to have similar compositions, most such interlopers can in principle be recognised by spectral properties which do not match those of the bulk of family members. A prominent example is 1 Ceres, the largest asteroid, which is an interloper in the family once named after it (the Ceres family, now the Gefion family).

Spectral characteristics can also be used to determine the membership (or otherwise) of asteroids in the outer regions of a family, as has been used e.g. for the Vesta family, whose members have an unusual composition.

Family types

As previously mentioned, families caused by an impact that did not disrupt the parent body but only ejected fragments are called cratering families. Other terminology has been used to distinguish various types of groups which are less distinct or less statistically certain from the most prominent "nominal families" (or clusters).

Clusters, clumps, clans and tribes

The term cluster is also used to describe a small asteroid family, such as the Karin cluster. [2] Clumps are groupings which have relatively few members but are clearly distinct from the background (e.g. the Juno clump). Clans are groupings which merge very gradually into the background density and/or have a complex internal structure making it difficult to decide whether they are one complex group or several unrelated overlapping groups (e.g. the Flora family has been called a clan). Tribes are groups that are less certain to be statistically significant against the background either because of small density or large uncertainty in the orbital parameters of the members.

List

Prominent families

Circle frame.svg
  •   Nysa: 19,073 (4.8%)
  •   Vesta: 15,252 (3.8%)
  •   Flora: 13,786 (3.5%)
  •   Eos: 9,789 (2.5%)
  •   Koronis: 5,949 (1.5%)
  •   Eunomia: 5,670 (1.4%)
  •   Hygiea: 4,854 (1.2%)
  •   Themis: 4,782 (1.2%)
  •   Hungaria: 2,965 (0.7%)
  •   All other families: 21,500 (5.4%)
  •   Background: 295,000 (74.0%)
Distribution of the most prominent families, other families and background asteroids (up to number 398,000) [3] :23

Among the many asteroid families, the Eos, Eunomia, Flora, Hungaria, Hygiea, Koronis, Nysa, Themis and Vesta families are the most prominent ones in the asteroid belt. For a complete list, see § All families .

Eos family
The Eos family (adj. Eoan; 9,789 members, named after 221 Eos)
Eunomia family
The Eunomia family (adj. Eunomian; 5,670 known members, named after 15 Eunomia) is a family of S-type asteroids. It is the most prominent family in the intermediate asteroid belt and the 6th-largest family with approximately 1.4% of all main belt asteroids. [3] :23
Flora family
The Flora family (adj. Florian; 13,786 members, named after 8 Flora) is the 3rd-largest family. Broad in extent, it has no clear boundary and gradually fades into the surrounding background population. Several distinct groupings within the family, possibly created by later, secondary collisions. It has also been described as an asteroid clan.
Hungaria family
The Hungaria family (adj. Hungarian; 2,965 members, named after 434 Hungaria)
Hygiea family
The Hygiea family (adj. Hygiean; 4,854 members, named after 10 Hygiea)
Koronis family
The Koronis family (adj. Koronian; 5,949 members, named after 158 Koronis)
Nysa family
The Nysa family (adj. Nysian; 19,073 members, named after 44 Nysa). Alternatively named Hertha family after 135 Hertha.
Themis family
The Themis family (adj. Themistian; 4,782 members, named after 24 Themis)
Vesta family
The Vesta family (adj. Vestian; 15,252 members, named after 4 Vesta)

All families

In 2015, a study identified 122 notable families with a total of approximately 100,000 member asteroids, based on the entire catalog of numbered minor planets, which consisted of almost 400,000 numbered bodies at the time (see catalog index for a current listing of numbered minor planets). [3] :23 The data has been made available at the "Small Bodies Data Ferret". [4] The first column of this table contains the family identification number or family identifier number (FIN), which is an attempt for a numerical labeling of identified families, independent of their currently used name, as a family's name may change with refined observations, leading to multiple names used in literature and to subsequent confusion. [3] :17

FINFamilyLbl# of Members Loc.
[note 1]
Taxonomy mean-
albedo
Parent body ·NotesCatLoMP
001 Hilda family HIL409rim C 0.04 153 Hilda; adj. Hildian; within the larger dynamical group with the same name.
(a–e–i: 3.7–4.2 AU; >0.07; <20°)
cat list
002Schubart familySHU352rimC0.03 1911 Schubart (within the dynamical Hilda group) cat list
003 Hungaria family H2965close E 0.35 434 Hungaria; located within the dynamical group of the same name.
(a–e–i: 1.78–2.0 AU; <0.18; 16°–34°)
cat list
004Hektor familyHEK12trojan 624 Hektor (Jupiter trojan) cat list
005Eurybates familyERY218trojan C P 0.06 3548 Eurybates (Jupiter trojan) cat list
006unnamed family0067trojan0.06 9799 Thronium (Jupiter trojan) list
007James Bond family [5] 0071AASP 9007 James Bond list
008Arkesilaos familyARK37trojan 20961 Arkesilaos (Jupiter trojan) cat list
009Ennomos familyENM30trojan0.06 4709 Ennomos (Jupiter trojan) cat list
010unnamed family01013trojan0.09 (247341) 2001 UV209 (Jupiter trojan) list
401 Vesta family V15252A V 0.35 4 Vesta (adj. Vestian) cat list
402 Flora family
(Ariadne family)
FLO13786A S 0.30 8 Flora (adj. Florian), also named after 43 Ariadne; typical asteroid clan. Not a legitimate asteroid family according to Carruba and Milani, instead, the Florian core region is labelled Belgica family and Duponta family (1338), respectively. [6] [7] cat list
403 Baptistina family BAP2500A X 0.16 298 Baptistina, merges with the Belgica family (1052) at 100 m/s according to Carruba [7] cat list
404 Massalia family MAS6424A S 0.22 20 Massalia, adj. Massalian, a-e-i: (2.37 to 2.45; 0.12 to 0.21; 0.4 to 2.4) cat list
405 Nysa–Polana complex
(Hertha family; Eulalia family)
NYS19073ASFC0.28
0.06
44 Nysa/142 Polana also known as the Hertha family (135 Hertha). Includes the Eulalia family (495 Eulalia) cat (44)
(142)
406Erigone familyERI1776ACX0.06 163 Erigone, adj. Erigonian. Can be joined with the dynamically different Martes family into a single collisional family (Src). cat list
407Clarissa familyCLA179A X 0.05 302 Clarissa cat list
408Sulamitis familySUL303A C 0.04 752 Sulamitis cat list
409Lucienne familyLCI142A S 0.22 1892 Lucienne cat list
410Euterpe familyEUT474AS0.26 27 Euterpe cat list
411Datura familyDAT6AS0.21 1270 Datura; Recently formed family with members: (60151), (90265), (203370), (215619) and (338309) cat list
412Lucascavin familyLCA3AS 21509 Lucascavin; members: (180255), (209570) cat list
413Klio familyKLI330A C 0.07 84 Klio cat list
414Chimaera familyCIM108ACX0.06 623 Chimaera cat list
415Chaldaea family
(Salli family)
CHL132A C 0.07 313 Chaldaea; alt. named after 1715 Salli by Masiero cat list
416Svea familySVE48ACX0.06 329 Svea cat list
417unnamed family4179A (108138) 2001 GB11 list
701 Phocaea family PHO1989A S 0.22 25 Phocaea cat list
501 Juno family JUN1684BS0.25 3 Juno (adj. Junonian) cat list
502 Eunomia family EUN5670BS0.19 15 Eunomia cat list
504Nemesis family
(Liberatrix or Zdeněkhorský family)
NEM1302C C 0.05 128 Nemesis (adj. Nemesian); also named after 58 Concordia (adj. Concordian) and 3827 Zdeněkhorský. Formerly Liberatrix family by Zappalà (1995) and Cellino (2002) cat list
505 Adeona family ADE2236BC0.07 145 Adeona cat list
506 Maria family
(Roma family)
MAR2940B S 0.25 170 Maria; alternatively named after 472 Roma. [8] cat list
507 Padua family
(Lydia family)
PAD1087C X 0.10 363 Padua; also known as Lydia family [C]  · 110 Lydia  ·adj. Paduan; Lydian cat list
508Aeolia familyAEO296CX0.17 396 Aeolia cat list
509Chloris familyCLO424C C 0.06 410 Chloris, adj. Chloridian cat list
510Misa familyMIS702BC0.03 569 Misa, adj. Misian cat list
511Brangäne familyBRG195B S 0.10 606 Brangäne cat list
512Dora familyDOR1259C C 0.05 668 Dora, adj. Dorian cat list
513Merxia familyMRX1215C S 0.23 808 Merxia, adj. Merxian cat list
514Agnia familyAGN2125CS0.18 847 Agnia cat list
515Astrid familyAST489C C 0.08 1128 Astrid, adj. Astridian cat list
516 Gefion family
(Ceres family; Minerva family)
GEF2547C S 0.20 1272 Gefion, adj. Gefionian; a-e-i: (2.74 to 2.82; 0.08 to 0.18; 7.4 to 10.5); also known as Ceres family (adj. Cererian) after 1 Ceres; and Minerva (adj. Minervian) family after 93 Minerva (identified interloper) cat list
517König familyKON354BCX0.04 3815 König cat list
518Rafita familyRAF1295B S 0.25 1644 Rafita, adj. Rafitian (namesake is a suspected interloper; not listed in family); members (1587) and (1658) cat list
519Hoffmeister familyHOF1819CCF 0.04 1726 Hoffmeister cat list
520Iannini familyIAN150B S 0.32 4652 Iannini cat list
521Kazuya familyKAZ44BS0.21 7353 Kazuya cat list
522Ino familyINO463CS0.24 173 Ino cat list
523Emilkowalski familyEMI4BS0.20 14627 Emilkowalski; members: (126761), (224559) and (256124) cat list
524Brugmansia family5243BS 16598 Brugmansia; members: (190603) and (218697) cat list
525Schulhof familySHF5BS0.27 2384 Schulhof; members: (81337), (140600), (271044), (286239) cat list
526unnamed family52658C C 0.06 (53546) 2000 BY6 list
527Lorre familyLOR2CC0.05 5438 Lorre; other member: (208099) cat list
528Leonidas familyLEO135BCX0.07 2782 Leonidas; identical to the Vibilia family: VIB (and listed as such); (4793) cat list
529Vibilia familyVIB180B C 0.06 144 Vibilia; namesake only listed in family by Zappalà, but not by Nesvorý; identical to the Leonidas family: LEO. cat list
530Phaeo familyPAE146C X 0.06 322 Phaeo cat list
531Mitidika familyMIT653B C 0.06 2262 Mitidika (not listed in family itself); members: (404) and (99) cat list
532Henan familyHEN1872B L 0.20 2085 Henan cat list
533Hanna familyHNA280CCX0.05 1668 Hanna cat list
534Karma familyKRM124BCX0.05 3811 Karma cat list
535Witt familyWIT1618C S 0.26 2732 Witt cat list
536Xizang familyXIZ275C0.12 2344 Xizang cat list
537Watsonia familyWAT99C L 0.13 729 Watsonia cat list
538Jones family (asteroids)JNS22B T 0.05 3152 Jones cat list
539Aëria familyAER272B X 0.17 369 Aeria cat list
540Julia family (asteroids)JUL33B S 0.19 89 Julia cat list
541Postrema familyPOS108CCX0.05 1484 Postrema cat list
801 Pallas family PAL128C B 0.16 2 Pallas (adj. Palladian) cat list
802Gallia familyGAL182C S 0.17 148 Gallia cat list
803Hansa familyHNS1094BS0.26 480 Hansa adj. Hansian; a-e-i: (~2.66; ~0.06; ~22.0°) [9] cat list
804Gersuind familyGER415BS0.15 686 Gersuind cat list
805Barcelona familyBAR306BS0.25 945 Barcelona cat list
806Tina familyTIN96C X 0.34 1222 Tina cat list
807Brucato familyBRU342BCX0.06 4203 Brucato cat list
601 Hygiea family HYG4854GCB 0.06 10 Hygiea cat list
602 Themis family THM4782G C 0.07 24 Themis (adj. Themistian) cat list
603Sylvia familySYL255rim X 0.05 87 Sylvia; family within Cybele group cat list
604Meliboea familyMEL444G C 0.05 137 Meliboea, adj. Meliboean cat list
605 Koronis family
(Lacrimosa family)
KOR5949D S 0.15 158 Koronis, also named after 208 Lacrimosa cat list
606 Eos family EOS9789E K 0.13 221 Eos cat list
607Emma familyEMA76F C 0.05 283 Emma cat list
608Brasilia familyBRA579D X 0.18 293 Brasilia, adj. Brazilian (namesake is a suspected interloper; not listed in family) cat list
609Veritas familyVER1294GCPD0.07 490 Veritas, adj. Veritasian; alt: Undina (Undinian) family after 92 Undina cat list
610 Karin family KAR541D S 0.21 832 Karin. Recently formed family located within the Koronis family. [3] :8,18 cat list
611Naëma familyNAE301D C 0.08 845 Naëma, adj. Naëmian cat list
612Tirela family
(Klumpkea family)
TIR1395G S 0.07 1400 Tirela, alternatively named after 1040 Klumpkea (AstDyS) cat list
613Lixiaohua family
(Gantrisch family)
LIX756GCX0.04 3556 Lixiaohua; although member 3330 Gantrisch is both larger and lower numbered (src) cat list
614Telramund family
(Klytaemnestra family)
TEL468E S 0.22 9506 Telramund; alternatively named after 179 Klytaemnestra by Masiero and by Milani cat list
615unnamed family615104DCX0.17 (18405) 1993 FY12 list
616Charis familyCHA808D C 0.08 627 Charis cat list
617Theobalda familyTHB376GCX0.06 778 Theobalda, adj. Theobaldian; a-e-i: (3.16 to 3.19; 0.24 to 0.27; 14 to 15) cat list
618Terentia familyTRE79D C 0.07 1189 Terentia cat list
619Lau familyLAU56D S 0.27 10811 Lau cat list
620Beagle familyBGL148G C 0.09 656 Beagle. Recently formed family is located within the Themis family (all members are also listed as Themistians). Includes 7968 Elst–Pizarro. [3] :7,8,18 cat list
621 Koronis family (II)K-2246D S 0.14 158 Koronis "second family" cat list
622Terpsichore familyTRP138D C 0.05 81 Terpsichore cat list
623Fringilla familyFIR134D X 0.05 709 Fringilla cat list
624Durisen familyDUR27DX0.04 5567 Durisen cat list
625Yakovlev familyYAK67D C 0.05 5614 Yakovlev cat list
626San Marcello familySAN144D X 0.19 7481 San Marcello cat list
627unnamed family62738DCX0.05 (15454) 1998 YB3 list
628unnamed family628248D S 0.10 (15477) 1999 CG1 list
629unnamed family62958DS0.21 (36256) 1999 XT17 list
630Aegle familyAEG99FCX0.07 96 Aegle cat list
631Ursula familyURS1466GCX0.06 375 Ursula cat list
632Elfriede familyELF63G C 0.05 618 Elfriede cat list
633Itha familyITH54D S 0.23 918 Itha cat list
634Inarradas familyINA38FCX0.07 3438 Inarradas cat list
635Anfimov familyANF58F S 0.16 7468 Anfimov cat list
636Marconia familyMRC34FCX0.05 1332 Marconia cat list
637unnamed family63764GCX0.05 (106302) 2000 UJ87 list
638Croatia familyCRO93G X 0.07 589 Croatia cat list
639Imhilde familyIMH43ECX0.05 926 Imhilde cat list
640Gibbs familyGBS8E 331P/Gibbs "P/2012 F5 (Gibbs)"
641Juliana familyJLI76ECX0.05 816 Juliana cat list
901Euphrosyne familyEUP2035G C 0.06 31 Euphrosyne cat list
902Alauda familyALA1294G B 0.07 702 Alauda cat list
903Ulla familyULA26rim X 0.05 909 Ulla; family within Cybele group cat list
904Luthera family
(Kartvelia family)
LUT163GX0.04 1303 Luthera; fam. is also named after 781 Kartvelia cat list
905Armenia familyARM40G C 0.05 780 Armenia cat list

Other families or dynamical groups

Other asteroid families from miscellaneous sources (not listed in the above table), as well as non-asteroid families include:

FamilyParentCatDescription
Aemilia family 159 Aemilia MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 62 members.
Alinda family 887 Alinda cat Alinda group described by projectpluto.com
Amneris family 871 Amneris cat Small family of 22 asteroids identified by Zappalà (1995). [11] Most members have been assigned to the encompassing complex of the Flora family by Nesvorný (2014). [3]
Anius family 8060 Anius MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 31 members.
Ashkova family 3460 Ashkova MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 59 members.
Astraea family 5 Astraea cat Large MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 6,169 members. Lowest-numbered members: (5), (91), (262), (355), (765) and (1121). Not a listed family by Zappalà (1995). [11] Considered a HCM-artifact by Nesvorný (2014) due to a resonant alignment (z1 = g + s − g6 − s6 = 0). [3] :19
Augusta family 254 Augusta cat Small family of 23 asteroids identified by Zappalà (1995). [11] Most members have been assigned to the Flora family by Nesvorný (2014). [3]
Ausonia family 63 Ausonia Single member. Unsourced. Member of the Vesta family according to AstDyS-2 and Nesvorný (2014). [3]
Bontekoe family 10654 Bontekoe MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 13 members.
Brokoff family 6769 Brokoff MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 58 members.
Bower family 1639 Bower Micro-family with 10 members as per Zappalà (1995). Adj. Bowerian. Alternative name Endymion (Endymionian) family after 342 Endymion. [C] All members: (1639), (3815), (8832), (14306), (15666), (22286), (32637), (85133), (120446) and (145685). [11] This family corresponds in large parts with the König family by Nesvorný (2014). [3]
Cindygraber family 7605 Cindygraber MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 19 members.
Clematis family 1101 Clematis cat MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 17 members. Subset of the large Alauda family as per Nesvorný (2014). [3] All members: (1101), (5360), (22044), (25982), (29963), (32240), (37628), (66174), (71688), (83362), (83790), (97516), (110030), (132961), (147858), (181960) and (223933).
Cybele group 65 Cybele cat Cybele group according to Asteroids, Meteorites, and Comets – by Linda T. Elkins-Tanton and projectpluto.com. Corresponding wiki-category lists a total of 32 members. Not a listed family in HCM by Zappalà (1995), Nesvorný (2014) and AstDyS-2 (Src), where these bodies are predominantly assigned to the background population. [11] [3]
Dejanira family 157 Dejanira cat Micro-family with 5 members as per Zappalà (1995). All members: (157), (2290), (5276), (10779) and (17377). [11] All belong to the background population according to Nesvorný (2014). [3]
Devine family 3561 Devine MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 19 members.
Duponta family 1338 Duponta MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 133 members.
Epeios family 2148 Epeios Jupiter trojan family according to Roig and Gil-Hutton (2008). Part of the Menelaus clan. [12]
Eumelos family 5436 Eumelos Jupiter trojan family according to Roig and Gil-Hutton (2008). Part of the Menelaus clan. [12]
Euryalos family 4007 Euryalos Jupiter trojan family according to Roig and Gil-Hutton (2008). Part of the Menelaus clan. [12]
Faïna family 751 Faïna cat Carbonaceous family with 12 identified members as per Zappalà (1995). [11] All members: (751), (2089), (2420), (3637), (3904), (5083), (8087), (10741), (10744), (11497), (12975) and (29086). Predominantly background population with 3 bodies belonging to the stony Maria family per Nesvorný (2014). Not a listed family at AstDyS-2 (Src)
Griqua group 1362 Griqua cat Griqua group (not a collisional family) described by projectpluto.com. A marginally unstable group of asteroids observed in the 2 :1 resonance with Jupiter.
Hanskya family 1118 Hanskya MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 116 members.
Haumea family Haumea (dwarf planet) cat This is a TNO-family. As of 2017, and current categorization, the family consists of 10 members (including parent body). [D]
Helio family 895 Helio MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 50 members.
Hestia family 46 Hestia cat Nesvorný moved family (formerly FIN 503) to candidate status, and (46) to background. [3] :19 Also background according to Milani and Knežević (AstDyS-2).
Higson family 3025 Higson MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 17 members.
Hippasos family 17492 Hippasos MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 7 members.
Huberta family 260 Huberta MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 26 members. Nesvorný moved family to candidate status. [3] :19
Kalchas family 4138 Kalchas Jupiter trojan family according to Roig and Gil-Hutton (2008). Part of the Menelaus clan. [12]
Laodica family 507 Laodica cat Category with 2 members. 507 Laodica and 635 Vundtia are core members of the Eos family according to AstDyS-2 (507; 635) and background asteroid per Nesvorný (507; 635), respectively. [3]
Levin family 2076 Levin MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 1534 members.
Liberatrix family 125 Liberatrix cat 3 listed members. 125 Liberatrix is a background asteroid according to AstDyS-2, and a member of the Nemesis family according to Nesvorný. [3] Background asteroid: 301 Bavaria (both AstDyS-2 and Nesvorný). 9923 Ronaldthiel is a core member of the Agnia family at AstDyS-2.
Makhaon family 3063 Makhaon Jupiter trojan family according to Roig and Gil-Hutton (2008). Part of the Menelaus clan. [12]
Marsili family 40134 Marsili MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 16 members.
Martes family 5026 Martes cat MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 481 members. Largest asteroids are members of the Erigone family according to Nesvorný (5026; 9879). [3]
Matterania family 883 Matterania MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 169 members.
Mecklenburg family 6124 Mecklenburg MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 78 members.
Melanthios family 12973 Melanthios Jupiter trojan family according to Roig and Gil-Hutton (2008). Part of the Menelaus clan. [12]
Menelaus family 1647 Menelaus Jupiter trojan family according Milani (1993). [13] Part of the Menelaus clan according to Roig and Gil-Hutton (2008). [12]
Nele family 1547 Nele MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 344 members.
Nocturna family 1298 Nocturna MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 186 members.
Nohavica family 6539 Nohavica cat Previously known as the "1982 QG" family. Second member: (9935) 1986 CP1 ; both are background asteroids according to AstDyS-2 and Nesvorný.
Podarkes family 13062 Podarkes Jupiter trojan family according to Roig and Gil-Hutton (2008). Part of the Menelaus clan. [12]
Prokne family 194 Prokne MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 379 members.
Reginita family 1117 Reginita cat Claimed subgroup of the Flora family. Background asteroid according to both AstDyS-2 and Nesvorný. [3]
Sinden family 10369 Sinden MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 24 members.
Takehiro family 8737 Takehiro MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 57 members. Nesvorný moved family to candidate status. [3] :19
Telamon family 1749 Telamon Jupiter trojan family according to Roig and Gil-Hutton (2008). Part of the Menelaus clan. [12]
Traversa family 5651 Traversa MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 56 members.
Univermoscow family 6355 Univermoscow MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 13 members.
Zhvanetskij family 5931 Zhvanetskij MBA-family (AstDys) according to Milani and Knežević (2014). [6] [10] Total of 23 members.
Legend:

See also

Notes

  1. "close" refers to asteroids inside the 9:2 resonance, "inner" refers to asteroids between the 9:2 and 4:1 resonance. A refers to between 4:1 and 3:1, B is 3:1 to 8:3, C is 8:3 to 5:2, D is 5:2 to 7:3, E is 7:3 to 9:4, F is 9:4 to 11:5, G is 11:5 to 2:1, "outer" refers to asteroids between the 2:1 and 11:6 resonance, and "rim" refers to asteroids beyond the 11:6 resonance.

Related Research Articles

Asteroid belt Circumstellar disk (accumulation of matter) in an orbit between those of Mars and Jupiter

The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes but much smaller than planets, called asteroids or minor planets. This asteroid belt is also called the main asteroid belt or main belt to distinguish it from other asteroid populations in the Solar System such as near-Earth asteroids and trojan asteroids.

15 Eunomia Main-belt asteroid

Eunomia is a very large asteroid in the inner asteroid belt. It is the largest of the stony (S-type) asteroids after 3 Juno. It is quite a massive asteroid, in 6th to 8th place. It is the largest Eunomian asteroid, and is estimated to contain 1% of the mass of the asteroid belt.

44 Nysa

Nysa is a large and very bright main-belt asteroid, and the brightest member of the Nysian asteroid family. It is classified as a rare class E asteroid and is probably the largest of this type.

The Eunomia or Eunomian family is a large asteroid family of S-type asteroids named after the asteroid 15 Eunomia. It is the most prominent family in the intermediate asteroid belt and the 6th-largest family with nearly six thousand known members, or approximately 1.4% of all asteroids in the asteroid belt.

The Vesta family is a family of asteroids. The cratering family is located in the inner asteroid belt in the vicinity of its namesake and principal body, 4 Vesta. It is one of the largest asteroid families with more than 15,000 known members and consists of mostly bright V-type asteroids, so-called "vestoids".

The Eos family is a very large asteroid family located in the outer region of the asteroid belt. The family of K-type asteroids is believed to have formed as a result of an ancient catastrophic collision. The family's parent body is the asteroid 221 Eos.

The Gefion family is an asteroid family located the in intermediate asteroid belt between 2.74 and 2.82 AU at inclinations of 7.4° to 10.5°. The family of S-type asteroids is named after 1272 Gefion and consists of more than 2,500 known members. It had previously been known as the Ceres family. It is still known as Minerva family, named after then thought parent body 93 Minerva, until it was identified to be an interloper into its own family.

682 Hagar

682 Hagar is an Eunomia asteroid from the central regions of the asteroid belt. It was discovered on 17 June 1909, by German astronomer August Kopff at the Heidelberg-Königstuhl State Observatory. The presumed S-type asteroid has a short rotation period of 4.9 hours and measures approximately 19 kilometers in diameter. Possibly inspired by the asteroid's provisional designation "1909 HA", it was named for the biblical woman Hagar.

848 Inna is a carbonaceous Themistian asteroid from the outer regions of the asteroid belt. It was discovered on 5 September 1915, by astronomer Grigory Neujmin at the Simeiz Observatory on the Crimean peninsula. The C-type asteroid measures approximately 33 kilometers in diameter, while its rotation period remains unknown. It was named after Russian astronomer Inna Nikolaevna Leman-Balanovskaya (1881–1945).

867 Kovacia

867 Kovacia is an elongated, dark asteroid and member of the Hygiea family from the outer regions of the asteroid belt. It was discovered on 25 February 1917, by astronomer Johann Palisa at the Vienna Observatory in Austria. The carbonaceous C/B-type asteroid has a rotation period of 8.7 hours and measures approximately 24 kilometers in diameter. It was named after Austrian physician Friedrich Kovacs (1861–1931).

812 Adele

812 Adele is an elongated Eunomia asteroid from the central regions of the asteroid belt. It was discovered on 8 September 1915, by Russian astronomer Sergey Belyavsky at the Simeiz Observatory on the Crimean peninsula. The presumed S-type asteroid has a rotation period of 5.9 hours and measures approximately 13 kilometers in diameter. It was likely named after the character "Adele" in the opera Die Fledermaus by Johann Strauss.

845 Naëma is a large asteroid and the parent body of the Naëma family located in the outer regions of the asteroid belt. It was discovered on 16 November 1916, by astronomer Max Wolf at the Heidelberg-Königstuhl State Observatory in southwest Germany. The carbonaceous C-type asteroid has a rotation period of 20.9 hours and measures approximately 54 kilometers in diameter on average, as it is likely elongated in shape. Any reference of the asteroid's name to a person is unknown.

Juno clump

The Juno clump is a probable main-belt asteroid family that share similar orbital elements to 3 Juno.

Flora family

The Flora family is a prominent family of stony asteroids located in the inner region of the asteroid belt. It is one of the largest families with more than 13,000 known members, or approximately 3.5% of all main-belt asteroids.

The Hygiea or Hygieanfamily is a grouping of dark, carbonaceous C-type and B-type asteroids in outer asteroid belt, the largest member of which is 10 Hygiea. About 1% of all known asteroids in the asteroid belt belong to this family.

The Massalia family is a family of asteroids in the inner asteroid belt, named after its parent body, 20 Massalia. It consists of S-type asteroids with very low inclinations, straddling the 1:2 resonances with Mars. There are more than 6,000 known Massalian asteroids.

The Nysa family is part of the Nysa–Polana complex, the largest cluster of asteroid families in the asteroid belt. It is located in the inner region of the asteroid belt, orbiting the Sun between 2.41 and 2.5 AU. Asteroids in this complex have eccentricities between 0.12 and 0.21 and inclinations of 1.4 to 4.3. The family derives its name from its most massive member, 44 Nysa. It has also been known as the Hertha family(adj. Herthian) named after 135 Hertha.

3430 Bradfield

3430 Bradfield (prov. designation: 1980 TF4) is a stony Agnia asteroid from the central regions of the asteroid belt, approximately 8 kilometers (5 miles) in diameter. It was discovered on 9 October 1980, by American astronomer Carolyn Shoemaker at the Palomar Observatory in California. The Sq-type asteroid was named after comet hunter William A. Bradfield.

6312 Robheinlein

6312 Robheinlein (prov. designation:1990 RH4) is a bright Augusta or background asteroid from the inner regions of the asteroid belt, that measures approximately 3.5 kilometers (2.2 miles) in diameter. It was discovered on 14 September 1990, by American astronomer Henry Holt at the Palomar Observatory in California. The uncommon L-type asteroid was named for American science fiction writer Robert A. Heinlein.

6189 Völk (prov. designation:1989 EY2) is a stony Vesta asteroid, approximately 4 kilometers (2.5 miles) in diameter, located in the inner regions of the asteroid belt. It was discovered on 2 March 1989, by Belgian astronomer Eric Elst at the La Silla Observatory in northern Chile. The S-type asteroid has a short rotation period of 2.9 hours. It was named for Elisabeth Völk, a staff member at ESO headquarters in Germany.

References

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  2. David Nesvorný, Brian L. Enke, William F. Bottke, Daniel D. Durda, Erik Ashaug & Derek C. Richardson Karin cluster formation by asteroid impact, Icarus 183, (2006) pp 296-311.
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Further reading