WATER-ICE PARTICLES IN ENCELADUS' PLUME: CHARACTERIZING THEIR NEAR INFRARED SPECTRAL DIVERSITY

Enceladus, Saturn's small icy satellite, is currently exhibiting plume activity and therefore providing direct access to samples from the interior. The plume material, mostly composed of water vapor and ice particles, has been extensively studied using various sensors onboard the NASA-ESA Cassini mission, which is currently orbiting Saturn.

Water-ice has diagnostic absorption signatures in the near infrared region, most notably around 3 microns. Our analysis of the near-infrared spectra of Enceladus' plume has highlighted variations in its spectral properties, which directly represent changes in the character of water-ice particles in the plume, most notably their particle size.

We are currently undertaking a systematic analysis of data from Cassini Visual and Infrared Mapping Spectrometer (VIMS) by considering parameters such as viewing geometry (phase angle effects), Enceladus' orbital position around Saturn and observation time (temporal aspects). This presentation would discuss the observed trends and their implications for evolution of the plume material.