http://arxiv.org/abs/2009.14103
Images of Europa’s surface taken by the Galileo Solid State Imager (SSI) show smooth features measuring a few kilometers, potentially resulting from eruptions of low-viscosity material. We estimate the volumes of four of these smooth features by producing digital elevation models (DEM) from Galileo/SSI images. We use the shape-from-shading method with special care to estimate the uncertainties on the produced DEMs and estimate the features’ volumes to be between ($5.710^{7}$ m$^{3}$ and ($2.710^{8}$ m$^{3}$. We discuss the implications for putative sub-surface liquid reservoir dimensions in case of eruptions induced from freezing reservoirs. We improved upon our previous cryovolcanic eruption model by considering a cycle of cryomagma freezing and effusion and by estimating the vaporized cryolava fraction once it spreads onto Europa’s surface. Our results show that the cryomagma reservoirs would have to be quite large to generate these smooth features (1 to 100 km$^{3}$ if the flow features result from a single eruption, and 0.4 to 60 km$^{3}$ for a full eruption cycle). The two future missions JUICE (ESA) and Europa Clipper (NASA) should reach Europa in the late 2020s. They shall give more information on those putative cryovolcanic regions that are interesting targets to understand the surface/interior exchanges.
E. Lesage, F. Schmidt, F. Andrieu, et. al.
Wed, 30 Sep 2020
60/86
Comments: N/A