Assessing the Plausibility of Past Cryovolcanism on Umbriel Using the Wunda Impact Crater

Abstract The imaged portion of Umbriel's surface is dark and cratered, suggesting limited geologic activity. However, bright deposits occupying the Wunda impact crater may be of endogenic origin, similar to proposed cryovolcanic sources for fresh bright material occupying Occator crater on Ceres. Here, we model the formation of Wunda using iSALE‐2D. Our goal is to determine whether Wunda's inferred morphology is consistent with the interior structure predicted for Umbriel and whether Wunda's interior might originate from impact‐induced cryovolcanism and/or was sourced from a subsurface ocean. We find that, if Wunda is indeed a complex crater, as coarsely resolved imagery suggests, Umbriel's ice shell may have been much thinner (50 km) and/or warmer (240 K) than predicted at present or subject to significant structural/compositional differences, such as abundant volatiles. These results help assess the thermal evolution of the Uranian satellites as potential ocean worlds.