SEARCHING FOR EUROPAN PLUMES: PAST, PRESENT, AND IN THE FUTURE

Recent Hubble Space Telescope observations and reprocessed data from the Galileo mission, suggest that plumes may be actively erupting at Jupiter’s moon, Europa (e.g. Roth et al, 2014, Sparks et al, 2016, 2017). However, these possible detections of plume activity are difficult to verify because of the very limited repeat detections. This could be due to substantial variability of plume activity on Europa (e.g. Rhoden et al, 2015). One potential source of variability would be if these plumes are partly controlled by tidal activity, similar to what seems to control the activity of Saturn’s moon Enceladus (e.g. Hurford et al., 2012). Here we determine the timing and magnitude of the diurnal and obliquity stresses acting on mapped structures on Europa. We expand on the work by Rhoden et al (2015) to include locations detected since that work, and include features identified on the USGS Global Geologic map (Leonard et al, 2020). We will present on which features could be candidates for detected plume source locations and where future observations may want to target for potential plume activity. To calculate the stresses, we use the open source numerical code SatStressGUI. This model assumes a 4-layer, homogeneous body. The outer 2 outer layers are the icy crust which is divided into an upper high-viscosity layer, and a lower, less viscous layer. The third layer must be liquid; for Europa it is assumed to be a global liquid water layer. The inner-most layer is the core or combined core and mantle. Stresses are calculated based on the properties of the satellite, the mass of Jupiter, and the eccentricity and obliquity of Europa. For this work, we only explore the possible contribution of diurnal tidal stresses and 0.1 degrees of obliquity.