Non-destructive collisions and the evolution of the orbits of binary asteroid systems in the Main Belt
Version of Record online: 14 AUG 2012
© 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS
Monthly Notices of the Royal Astronomical Society
Volume 425, Issue 2, pages 1492–1503, 11 September 2012
How to Cite
Dell'Oro, A., Cellino, A. and Paolicchi, P. (2012), Non-destructive collisions and the evolution of the orbits of binary asteroid systems in the Main Belt. Monthly Notices of the Royal Astronomical Society, 425: 1492–1503. doi: 10.1111/j.1365-2966.2012.21643.x
- Issue online: 22 AUG 2012
- Version of Record online: 14 AUG 2012
- Manuscript Accepted: 3 JUL 2012
- Manuscript Received: 29 JUN 2012
- Italian National Institute for Astrophysics (INAF)
- minor planets, asteroids: general
The effect of collisions on the stability of binary asteroids is discussed. The following mechanisms are taken into account: (1) complete disruption of one of the members of the system and (2) increase of linear momentum imparted by non-disruptive collisions. The latter effect is found to progressively increase the orbital energy of the systems up to the limit of binary gravitational instability.
We focus on the case of binary asteroids belonging to the Main Belt. We show that the probability that a binary system ‘evaporates’ before collisional disruption of one of the two members is not negligible. As a consequence, the expected lifetime of a binary system can decrease significantly. Binary ‘evaporation’ causes the two former members to continue to exist as independent asteroids forming a so-called asteroid pair.
The efficiency of this mechanism critically depends on the properties of the binary system and on the collisional environment. Several different scenarios have been taken into account concerning the size distribution of possible projectiles in the asteroid Main Belt, while the estimate of the fragmentation threshold in energetic impacts is based on the work of Benz & Asphaug. We estimate the expected average lifetime of a binary system as a function of different parameters including the size of the primary, the size ratio of the members and the orbital properties of the system. Moreover, the expected lifetimes of binary asteroids which are known today have been computed as a function of different possible collisional environments.