FOSSIL. II. The Rotation Periods of Small-sized Hilda Asteroids

Chan Kao Chang, Ying Tung Chen, Wesley C. Fraser, Matthew J. Lehner, Shiang Yu Wang, Mike Alexandersen, Young Jun Choi, A. Paula Granados Contreras, Takashi Ito, Youngmin Jeongahn, Jianghui Ji, J. J. Kavelaars, Myung Jin Kim, Samantha M. Lawler, Jian Li, Zhong Yi Lin, Patryk Sofia Lykawka, Hong Kyu Moon, Surhud More, Marco Muñoz-GutiérrezKeiji Ohtsuki, Rosemary E. Pike, Tsuyoshi Terai, Seitaro Urakawa, Fumi Yoshida, Hui Zhang, Haibin Zhao, Ji Lin Zhou

研究成果: 雜誌貢獻期刊論文同行評審


Using the high-cadence lightcurves collected from the FOSSIL survey, rotation periods of 17 small (diameter 1 km < D < 3 km) Hilda asteroids (hereinafter Hildas) were obtained. Combined with the previously measured rotation periods of Hildas, a spin-rate limit appears at around 3 hr. Assuming rubble-pile structures for the Hildas, a bulk density of 1/41.5 g cm-3 is required to withstand this spin-rate limit. This value is similar to that of the C-type asteroids (1.33 g cm-3) and higher than the 1/41 g cm-3 bulk density of the Jupiter Trojans. This suggests that the Hildas population may contain more C-type asteroids than expected, and the limit at 3 hr simply reflects the spin-rate limit for C-type asteroids. In addition, a Hilda superfast rotator was found, which has a rotation period of 1.633 hr and an estimated diameter of 0.7 km. This object is unlikely to be explained by a rubble-pile or monolithic structure.

期刊Astrophysical Journal, Supplement Series
出版狀態已出版 - 1 3月 2022


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