Article,

Cassini/VIMS observation of an Io post-eclipse brightening event

, , , , , , , , , , , and .
Icarus, 172 (1): 141--148 (2004)

Abstract

During the Cassini-Jupiter flyby, VIMS observed Io at different phase angles, both in full sunlight and in eclipse. By using the sunlight measurements, we were able to produce phase curves in the visual through all the near infrared wavelengths covered by the VIMS instrument (0.85-5.1 mum). The phase angle spanned from similar to2degrees to similar to120degrees. The measurements, done just after To emerged from Jupiter's shadow, show an increase of about 15% in Io's reflectance with respect to what would be predicted by the phase curve. This behavior is observed at wavelengths > 1.2 mum. Moreover, just after emergence from eclipse an increase of about 25% is observed in the depth of SO2 frost bands at 4.07 and 4.35 mum. At 0.879 < lambda < 1.04 mum the brightening is 10-24%. Below lambda = 0.879 mum the brightening, if present, should be less than the precision of our measurements (similar to5%). Apparently, these observations are not explained neither by a diverse spatial distribution of SO2 on the Io' surface nor by atmospheric SO2 condensation on the surface during the eclipse. (C) 2004 Elsevier Inc. All rights reserved.

Tags

Users

  • @svance

Comments and Reviews