Astrophysics webinar
Laboratory radiation studies on Europa’s icy surface
Speaker: Sankhabrata Chandra (California Institute of Technology, USA)
Jupitar’s icy moon Europa is predicted to be habitable because of its vast ocean underneath its thick icy shell. To understand the habitability, NASA’s Europa Clipper Mission will be launching on October 2024, and will measure the surface and atmospheric composition, temperatures, ice thickness, etc. through its different remote sensing instruments and chemical analysis instrument such as mass spectrometer. Our laboratory study is currently establishing the reference data for the mass spectrometer that is critical for defining the requirements for sample collection and analysis from Europa’s atmosphere. Europa is continuously bombarded by solar photons as well as energetic electrons, protons, and ions from the magnetospheric torus of Jupiter. Depending on the energy, electrons can penetrate up to one meter on the icy surface of Europa, chemically alter the surface, and eject sputtered radiation products into the atmosphere. Investigating the radiation sputtering on the ice surface is important to understand the exchange between Europa’s surface and its atmosphere. If biotic or abiotic organics are present near the surface of Europa, the radiation products are expected to be sputtered into Europa's tenuous atmosphere and potentially detected by in-situ mass spectrometers on board the Europa Mission spacecraft. To mimic Europa’s surface conditions at JPL's Ice Spectroscopy Lab (ISL), I used an ultrahigh vacuum system coupled with a 2 keV electron source and a mass spectrometer to study the radiation sputtering of organics at different Europa surface temperatures. In the presentation, I will show how different types of materials emit specific sputtered products, and any unique sputtered product can be used to link the local surface composition with Europa’s atmosphere.