Did Saturn’s Rings Form During The Late Heavy Bombardment? Accepted for publication in ICARUS on October 31, 2008 arXiv:0809.5073 Sébastien CHARNOZ * UMR AIM, Université Paris Diderot/CEA/CNRS CEA/SAp, Centre de l’Orme Les Merisiers 91191 Gif-Sur-Yvette Cedex France Alessandro MORBIDELLI Observatoire de la Côte d’Azur OCA, B.P. 4229, 06304 Nice Cedex 4, France Luke DONES Southwest Research Institute 1050 Walnut St., Suite 300, Boulder, Colorado 80302, USA Julien SALMON UMR AIM, Université Paris Diderot/CEA/CNRS CEA/SAp, Centre de l’Orme Les Merisiers 91191 Gif-Sur-Yvette Cedex France Pages = 39 Figures = 9 Tables= 3 * : To whom correspondence should be addressed :
[email protected] 1 Abstract : The origin of Saturn’s massive ring system is still unknown. Two popular scenarios - the tidal splitting of passing comets and the collisional destruction of a satellite - rely on a high cometary flux in the past. In the present paper we attempt to quantify the cometary flux during the Late Heavy Bombardment (LHB) to assess the likelihood of both scenarios. Our analysis relies on the so-called “Nice model” of the origin of the LHB (Tsiganis et al., 2005; Morbidelli et al., 2005; Gomes et al., 2005) and on the size distribution of the primordial trans-Neptunian planetesimals constrained in Charnoz & Morbidelli (2007). We find that the cometary flux on Saturn during the LHB was so high that both scenarios for the formation of Saturn rings are viable in principle. However, a more detailed study shows that the comet tidal disruption scenario implies that all four giant planets should have comparable ring systems whereas the destroyed satellite scenario would work only for Saturn, and perhaps Jupiter.