A dark asteroid family in the Phocaea region

Abstract

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 sub-kilometer 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$\pm$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 H<19.4 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.

Accepted for publication in AJ

References in corpus (9)

• Solar System evolution from compositional mapping of the asteroid belt
• Asteroid family ages
• Thermal inertia of main belt asteroids smaller than 100 km from IRAS data
• Near-infrared colors of minor planets recovered from VISTA - VHS survey (MOVIS)
• On the Ages of Resonant, Eroded and Fossil Asteroid Families
• Yarkovsky V-shape identification of asteroid families
• P/2006 VW139: A Main-Belt Comet Born in an Asteroid Collision?
• Constraints on the original ejection velocity fields of asteroid families
• On the highly inclined $v_W$ leptokurtic asteroid families

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