New coverage by, not Science, but a sister title, Science Advances (this is becoming a pattern). For 22 Aug (vol. 11, #34):
Courville, S. W. Castillo-Rogez, J. C. Melwani Daswani, M. et al. Core metamorphism controls the dynamic habitability of mid-sized ocean worlds—The case of Ceres sciadv.adt3283
Celebi, H. F. Andrews, A. J. Pothos, I. et al. The origin of complex crater formation during high-speed impacts sciadv.adx0294
Ceres: arguably one of the comet-asteroid transition objects, except… it’s huge. No comet has ever been observed at the size of Ceres, or even of the order of magnitude of Ceres. Regardless, Ceres contains water, and bleeds some off to space. It is thus a candidate world (to various people, to various degrees) for extraterrestrial habitats and life. Hence Courville et al.: they find that, depending on certain assumptions (not literally certain at all), Ceres may have had a subsurface, habitable ocean for millions of years during the earlier eons of the Solar System. Nowadays, not so much.
Those Ceres water emissions are associated with craters, and big ones at that- water is not stable on the Cererean surface for the age of the Solar System. Either it must be covered by overburden and lag deposits, or it’s a temporary ice structure, being replenished from below. Celebi et al. use experimental astronomy (laboratory replication) to put more decimal places on our understanding of crater physics. A surprising find: complex craters (ones with central substructure) are technically possible even at small sizes. The incoming impactor just has to be that much faster.