Fates of satellite ejecta in the Saturn system, II

• Published in: Icarus (New York, N.Y. 1962) Vol. 284; pp. 70 - 89
• Main Authors: Alvarellos, José Luis, Dobrovolskis, Anthony R., Zahnle, Kevin J., Hamill, Patrick, Dones, Luke, Robbins, Stuart
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.03.2017
• Subjects: Cratering; Craters; Decay; Dynamics; Ejecta; Fragments; Impact processes; Longitude; Meters; Mimas; Satellites; Saturn; Saturn satellites; Impact processes; Cratering; Satellites; Saturn; Dynamics
• ISSN: 0019-1035; 1090-2643
• DOI: 10.1016/j.icarus.2016.10.028

•A ‘transfer efficiency matrix’ among Saturn’s moons is obtained.•Sesquinary crater diameters the icy moons of Saturn range from ‘few meters’ to ’few kilometers’.•Sesquinary craters in the icy moons of Saturn are created in the strength cratering regime.•The most likely place to find putative sesquinary craters is the antapex of Mimas. We assess the fates of ejecta from the large craters Aeneas on Dione and Ali Baba on Enceladus (161 and 39  km in diameter, respectively), as well as that from Herschel (130  km in diameter) on Mimas. The ejecta are treated either as ‘spalls’ launched from hard surfaces, or as ‘rubble’ launched from a weak rubble pile regolith. Once in orbit we consider the ejecta as massless test particles subject to the gravity of Saturn and its classical satellites. The great majority of escaped ejecta get swept up by the source moons. The best fit to the ejecta population decay is a stretched exponential with exponent near 1/2 (Dobrovolskis et al., Icarus 188, 481–505, 2007). We bracket the characteristic ejecta sizes corresponding to Grady–Kipp fragments and spalls. Based on this and computed impact velocities and incidence angles, the resulting sesquinary craters, if they exist, should have diameters on the order of a few meters to a few km. The observed longitude distribution of small craters on Mimas along with the findings of Bierhaus et al. that small moons should not have a secondary crater population (Icarus 218, 602–621, 2012) suggest that the most likely place to find sesquinary craters in the Saturn system is the antapex of Mimas.