The Pallas family of asteroids is a grouping of B-type asteroids at very high inclinations in the intermediate main belt (Cellino et al (2002)). The namesake is 2 Pallas, an extremely large asteroid with a mean diameter of about 530 km. The remaining bodies are far smaller (the largest being 5222 Ioffe with an estimated diameter of 22 km), which indicates that this is probably a so-called cratering family composed of ejecta from impacts onto the parent body 2 Pallas.
From the diagram, their proper orbital elements lie in the approximate ranges
| ap | ep | ip | |
|---|---|---|---|
| min | 2.71 AU | 0.25 | 32° |
| max | 2.79 AU | 0.31 | 34° |
At the present epoch, the range of osculating orbital elements of the members (by comparison to the MPCORB database [1]) is about
| a | e | i | |
|---|---|---|---|
| min | 2.71 AU | 0.13 | 30° |
| max | 2.79 AU | 0.37 | 38° |
The family appears to be genuinely derived from impacts onto Pallas due to the preponderance of the otherwise rare B spectral type among its members. The grouping was first noted by Kiyotsugu Hirayama in 1928, and later by Brouwer (1951), Kozai (1979), and Lemaitre&Morbidelli (1994).
References
- A. Lemaitre & A. Morbidelli, Proper elements for highly inclined asteroidal orbits, Celestial Mechanics and Dynamical Astronomy, Vol. 60, pp. 29 (1994).
- Y. Kozai [http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1979IAUS...81..231K&db_key=AST&data_type=HTML&format=&high=43ee033a4808372 Secular perturbations of asteroids and comets In: Dynamics of the solar system; Proceedings of the Symposium, Tokyo, Japan, May 23-26, 1978. Dordrecht, D. Reidel Publishing Co., 1979, p. 231-236; Discussion, p. 236, 237.
- 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).
- MPCORB orbit database
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| Vulcanoids · Near-Earth asteroids · Main belt · Jupiter Trojans · Centaurs · Damocloids · Neptune Trojans · Comets · Trans-Neptunians (Kuiper belt • Scattered disc objects • Oort cloud) |
| For other objects and regions, see Asteroid groups and families, Binary asteroids, Asteroid moons, meteoroids and the Solar System. For a complete listing, see List of asteroids. See also Pronunciation of asteroid names and Meanings of asteroid names. |
