文章基本信息

标题：A Dark Asteroid Family in the Phocaea Region
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作者：Bojan Novaković ; Georgios Tsirvoulis ; Mikael Granvik 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2017
卷号：153
期号：6
DOI：10.3847/1538-3881/aa6ea8
语种：English
出版社：American Institute of Physics
摘要：We report the discovery of a new asteroid family among the dark asteroids residing in the Phocaea region the Tamara family. We make use of available physical data to separate asteroids in the region according to their surface reflectance properties, and establish the membership of the family. We determine the slope of the cumulative magnitude distribution of the family, and find it to be significantly steeper than the corresponding slope of all the asteroids in the Phocaea region. This implies that subkilometer dark Phocaeas are comparable in number to bright S-type objects, shedding light on an entirely new aspect of the composition of small Phocaea asteroids. We then use the Yarkovsky V-shape based method and estimate the age of the family to be 264 ± 43 Myr. Finally, we carry out numerical simulations of the dynamical evolution of the Tamara family. The results suggest that up to 50 Tamara members with absolute magnitude may currently be found in the near-Earth region. Despite their relatively small number in the near-Earth space, the rate of Earth impacts by small, dark Phocaeas is non-negligible.
关键词：celestial mechanics;minor planets; asteroids: general Supporting material: machine-readable table