Did the Hilda collisional family form during the late heavy bombardment?
Article first published online: 2 MAY 2011
© 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS
Monthly Notices of the Royal Astronomical Society
Volume 414, Issue 3, pages 2716–2727, July 2011
How to Cite
Brož, M., Vokrouhlický, D., Morbidelli, A., Nesvorný, D. and Bottke, W. F. (2011), Did the Hilda collisional family form during the late heavy bombardment?. Monthly Notices of the Royal Astronomical Society, 414: 2716–2727. doi: 10.1111/j.1365-2966.2011.18587.x
- Issue published online: 21 JUN 2011
- Article first published online: 2 MAY 2011
- Accepted 2011 February 22. Received 2011 February 3; in original form 2011 January 5
- methods: numerical;
- celestial mechanics;
- minor planets, asteroids: general
We model the long-term evolution of the Hilda collisional family located in the 3/2 mean-motion resonance with Jupiter. Its eccentricity distribution evolves mostly due to the Yarkovsky/YORP effect and assuming that (i) impact disruption was isotropic and (ii) albedo distribution of small asteroids is the same as for large ones, we can estimate the age of the Hilda family to be 4+0−1 Gyr. We also calculate collisional activity in the J3/2 region. Our results indicate that current collisional rates are very low for a 200-km parent body such that the number of expected events over gigayears is much smaller than 1.
The large age and the low probability of the collisional disruption lead us to the conclusion that the Hilda family might have been created during the late heavy bombardment (LHB) when the collisions were much more frequent. The Hilda family may thus serve as a test of orbital behaviour of planets during the LHB. We have tested the influence of the giant-planet migration on the distribution of the family members. The scenarios that are consistent with the observed Hilda family are those with fast migration time-scales ≃0.3–3 Myr, because longer time-scales produce a family that is depleted and too much spread in eccentricity. Moreover, there is an indication that Jupiter and Saturn were no longer in a compact configuration (with period ratio PS/PJ > 2.09) at the time when the Hilda family was created.