Detection Sensitivity for the Gemini Planet Imager (GPI) to Potential
Europa Plumes
Abstract
There has been possible evidence from ground based telescopes for plumes
of water emanating from Europa’s ice shell. Because of their potential
connection to the subsurface ocean these plumes are of significant
interest as targets for the in-situ instruments on upcoming NASA and ESA
missions to the Jovian system. Their potential similarity to
tidally-modulated plumes observed at Enceladus have led to speculation
that the occurrence of these plumes could be predicted accurately enough
to plan in-situ sampling. However, the plumes could be the result of
stochastic processes releasing near surface water from the ice shell and
may not occur during the missions at all. Better observational
constraints on plume distribution, predictability, and character would
provide critical information for planning operations and measurements on
the upcoming missions to Europa. The aim of this study is to demonstrate
capability of the Gemini Planet Imager (GPI) for this task, modeling the
detectability of Enceladus-like plumes on the surface of Europa using
polarimetry. The polarized signal from an Encleadus sized plume is
approximated by Mie scattering from micron-scale ice particulates at 1.5
- 1.8 µm. Ground-based observations with a nearly automated facility
such as GPI could allow daily searches for plumes and enable
dramatically more informed mission planning, increasing the potential
for habitability characterization and even potentially life detection.