Gefion family

The Gefion family (FIN: 516; adj. Gefionian; also known as the Ceres family or the Minerva family) is an asteroid family located in the 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.

Properties

The members have proper orbital elements in the approximate rangesaccording to the HCM analysis by V. Zappalà, Ph. Bendjoya, A. Cellino, P. Farinella and C. Froeschlé, Asteroid Families: Search of a 12,487-Asteroid Sample Using Two Different Clustering Techniques, Icarus, Volume 116, Issue 2 (August 1995), pages 291–314

ap ep ipmin 2.74 AU 0.120 8.6°max 2.82 AU 0.148 9.6°

At the present epoch, the range of osculating orbital elements of these core members is

a e i min 2.74 AU 0.081 7.4° max 2.82 AU 0.18 10.5°

The namesake is 1272 Gefion. The family is fairly large, e.g. the Zappala 1995 analysis found about a hundred core members. A search of a recent proper element databaseAstDys found 766 objects (about 0.8% of the total) lying within the region defined by the first table above.

2631 Zhejiang has a diameter of 34 km, and is the largest core member whose diameter has been reliably estimated, although 2911 Miahelena is brighter, and would have a rough diameter of about 47 km, given the same (very low) albedo of 0.025.

Alternative name and interlopers

Until recently, this family was known as the Ceres family (adj. Cererean) or the Minerva family (adj. Minervian) after 1 Ceres (the largest asteroid) or 93 Minerva. However, spectroscopic analyses showed that these largest members were in fact interlopers in their own family,A. Cellino et al. Spectroscopic Properties of Asteroid Families, in Asteroids III, p. 633-643, University of Arizona Press (2002). (Table on page 636, in particular). having a different spectral class from the bulk of the members. Other known interlopers are 255 Oppavia, 374 Burgundia, 2507 Bobone, and 2559 Svoboda.Identified by inspection of the SMASSII data set , S.J. Bus and R.P. Binzel, Phase II of the Small Main-Belt Asteroid Spectroscopic Survey, Icarus Vol. 158, p. 106 (2002). This left the fairly minor asteroid 1272 Gefion as the lowest-numbered member.

List of members

This is a list of the known family members, without the above-mentioned interlopers.

Name a (AU) e 1272 Gefion 2.78385 0.15170 1433 Geramtina 2.79948 0.16918 1751 Herget 2.79319 0.17242 1839 Ragazza 2.79898 0.16824 2053 Nuki 2.80260 0.14050 2157 Ashbrook 2.78440 0.11071 2373 Immo 2.79433 0.17339 2386 Nikonov 2.81456 0.15728 2493 Elmer 2.78777 0.17198 2521 Heidi 2.79475 0.08893 2595 Gudiachvili 2.78595 0.14340 2631 Zhejiang 2.79730 0.16070 2801 Huygens 2.79969 0.17422 2875 Lagerkvist 2.79792 0.09969 2905 Plaskett 2.80233 0.09847 2911 Miahelena 2.79520 0.09303 2977 Chivilikhin 2.78884 0.16849 3724 Annenskij 2.76293 0.16535 3788 Steyaert 2.79307 0.10127 3860 Plovdiv 2.80586 0.15548 3910 Liszt 2.79442 0.13349 3964 Danilevskij 2.75822 0.16608 4020 Dominique 2.77626 0.15885 4096 Kushiro 2.80989 0.15066 4182 Mount Locke 2.79806 0.13498 4702 Berounka 2.79387 0.09181 5159 Burbine 2.78979 0.10861 5401 Minamioda 2.79463 0.15238 Name a (AU) e 2.80083 0.17319 5685 Sanenobufukui 2.79967 0.09267 5712 Funke 2.77496 0.16644 5823 Oryo 2.77638 0.16166 5955 Khromchenko 2.80234 0.09628 6044 Hammer-Purgstall 2.77489 0.15517 6078 Burt 2.80392 0.17351 6211 Tsubame 2.75642 0.09601 6594 Tasman 2.78152 0.15916 7094 Godaisan 2.78088 0.16534 7211 Xerxes 2.79870 0.16302 7272 Darbydyar 2.78220 0.09822 (7397) 1986 QS 2.78255 0.16568 7451 Verbitskaya 2.81240 0.16818 2.78349 0.10158 7651 Villeneuve 2.78245 0.14156 7735 Scorzelli 2.75694 0.16628 2.78591 0.09965 8440 Wigeon 2.78016 0.14078 8451 Gaidai 2.77253 0.16753 2.76992 0.15337 2.78176 0.15170 8819 Chrisbondi 2.78098 0.17028 2.79053 0.11959 9511 Klingsor 2.76784 0.14054 10245 Inselsberg 2.78004 0.09434 2.79360 0.15011 10649 VOC 2.81578 0.12154 Name a (AU) e 10665 Ortigão 2.79851 0.15765 12275 Marcelgoffin 2.76315 0.15291 12279 Laon 2.76990 0.09282 2.81210 0.10526 2.76810 0.16222 2.76575 0.17269 2.81525 0.15026 2.78514 0.15738 2.78785 0.17691 2.78987 0.17546 19994 Tresini 2.77468 0.17725 2.75828 0.11401 2.76196 0.10315 2.81391 0.17207 2.80445 0.18117 (26099) 1989 WH 2.76196 0.14457 (26799) 1979 XL 2.78649 0.11048 2.79852 0.15112 2.76377 0.14769 2.77225 0.10578 2.75702 0.12711 2.76469 0.16515 2.74368 0.08177 2.77635 0.10965 2.76154 0.11756 2.79337 0.16135 2.78491 0.17877 2.8035 0.1627

References The asteroid families data set is taken from with updated names and numbers as of April 2005