CASSINI/altimeter and VIMS complementarity: example using observations over the same area from Ta and T13 Titan's flybys

• Main Authors: Crapeau, M., Rodriguez, S., Le Mouélic, Stéphane, Paillou, Philippe, Sotin, C., Wall, S.
• Other Authors: Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Laboratoire d'Astrophysique de Bordeaux Pessac (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2006
• Subjects: [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]; [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]; Antarctic; The Antarctic; Titan; Antarc*
• Online Access: https://hal.science/hal-00129685

The altimeter mode of the Ku-band RADAR experiment onboard the Cassini-Huygens mission has been designed primarily for the study of Titan's surface topography. Inspired by what is done on the Earth in icy contexts like in the Antarctic, Cassini altimetry data can also be used to retrieve the radar reflectivity of Titan's surface and thus, information about its nature. Our first study shows clear contrasts of the radar reflectivity along the altimeter track acquired during the first Titan flyby (Ta). This distinct decrease in radar reflectivity is somewhat correlated with a slight surface height variation. The 13th Titan flyby (T13) provided us VIMS (Visual and Infrared Mapping Spectrometer, operating between 0.3 and 5.1 µm) medium resolution observations of the same region. Infrared I/F along the Ta altimeter track presents a very strong correlation with the computed radar reflectivity. These correlations between infrared I/F and radar reflectivity variations indicate a change in the surface nature and the presence of a clearly defined surface structure under the track. VIMS 2.03/1.27 µm channels ratio transect along the altimeter track also suggests a local enrichment in water ice associated with a smooth depression, maybe witnessing ancient channels.