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The Pallas or Palladian family of asteroids is a grouping of B-type asteroids at very high inclinations in the intermediate asteroid belt (Cellino et al. (2002)). It was first noted by Kiyotsugu Hirayama in 1928. The namesake of the family is 2 Pallas, an extremely large asteroid with a mean diameter of about 550 km. The remaining bodies are far smaller; the largest is 5222 Ioffe with an estimated diameter of 22 km. This, along with the preponderance of the otherwise rare B spectral type among its members, indicates that this is likely a ''cratering'' family composed of ejecta from impacts on Pallas. Another suspected Palladian is 3200 Phaethon, the parent body of the Geminid meteor shower.〔("Exploding Clays Drive Geminids Sky Show?", 2010 October 12 )〕 From the diagram, their proper orbital elements lie in the approximate ranges At the present epoch, the range of osculating orbital elements of the members (by comparison to the MPCORB database ()) is about == References == * A. Lemaitre & A. Morbidelli, ''(Proper elements for highly inclined asteroidal orbits )'', Celestial Mechanics and Dynamical Astronomy, Vol. 60, pp. 29 (1994). * Y. Kozai ''(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 ) 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pallas family」の詳細全文を読む スポンサード リンク
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