Dynamical group of asteroids
The Cybele asteroids (also known as the "Cybeles") are a dynamical group of asteroids , named after the asteroid 65 Cybele .[ 1] Considered by some as the last outpost of an extended asteroid belt , the group consists of just over 2000 members and a few collisional families .[ 2] [ 3] The Cybeles are in a 7:4 orbital resonance with Jupiter . Their orbit is defined by an osculating semi-major axis of 3.27 to 3.70 AU ,[ 2] with an eccentricity of less than 0.3,[ 1] and an inclination less than 30°.[ 2]
The dynamical Cybele group is located adjacent to the outermost asteroid belt , beyond the Hecuba gap – the 2:1 resonant zone with Jupiter, where the Griqua asteroids are located – and inside the orbital region of the Hilda asteroids (3:2 resonance), which are themselves followed by the Jupiter trojans (1:1 resonance) further out.
Description
Three known asteroid families exist within the Cybele group: the Sylvia family (603 ), the Huberta family and the Ulla family (903 ). A potential fourth family is a small cluster with the parent body (45657) 2000 EK .[ 2] A fifth family, named after 522 Helga , was identified in 2015.[ 3]
The Cybele asteroids 87 Sylvia and 107 Camilla are triple systems with more than one satellite . Other large members include 121 Hermione , 76 Freia , 790 Pretoria , and 566 Stereoskopia .[ 1]
The group is thought to have formed from the breakup of a larger object in the distant past.[ 1] While most members are C- and X-type asteroids , NASA's Wide-field Infrared Survey Explorer also measured albedos of some Cybele asteroids that are typical for stony S-type asteroids .[ 2]
List
Total of 2034 Cybeles with osculating semi-major axis between 3.28 and 3.7 AU. Low numbered members of the collisional Sylvia (SYL) and smaller Ulla (ULA) families are also marked.
See also
References
^ a b c d Elkins-Tanton, Linda T. (2010). Asteroids, Meteorites, and Comets . Infobase. p. 96. ISBN 9781438131863 . Retrieved 27 April 2018 .
^ a b c d e Carruba, V.; Domingos, R. C.; Nesvorný, D.; Roig, F.; Huaman, M. E.; Souami, D. (August 2013). "A multidomain approach to asteroid families' identification" . Monthly Notices of the Royal Astronomical Society . 433 (3): 2075– 2096. arXiv :1305.4847 . Bibcode :2013MNRAS.433.2075C . doi :10.1093/mnras/stt884 . S2CID 118511004 .
^ a b Carruba, V.; Nesvorný, D.; Aljbaae, S.; Huaman, M. E. (July 2015). "Dynamical evolution of the Cybele asteroids" . Monthly Notices of the Royal Astronomical Society . 451 (1): 244– 256. arXiv :1505.03745 . Bibcode :2015MNRAS.451..244C . doi :10.1093/mnras/stv997 . S2CID 119246717 .