The collapse of Io's primary atmosphere in Jupiter eclipse

DOI: 
10.1002/2016JE005025
Publication date: 
01/08/2016
Main author: 
Tsang C.C.C.
IAA authors: 
Lopez-Valverde, M.A.
Authors: 
Tsang C.C.C., Spencer J.R., Lellouch E., Lopez-Valverde M.A., Richter M.J.
Journal: 
Journal of Geophysical Research E: Planets
Refereed: 
Yes
Publication type: 
Article
Volume: 
121
Pages: 
1400-1410
Number: 
Abstract: 
Volcanic outgassing due to tidal heating is the ultimate source of a tenuous SO2 atmosphere around Jupiter's moon Io. The question of whether SO2 frost on the surface plays a part, and to what degree, in maintaining Io's atmosphere with the constant volcanic outgassing is still debated. It is believed that for a sublimation-supported atmosphere, the primary atmosphere should collapse during eclipses by Jupiter, as the SO2 vapor pressure is strongly coupled to the temperature of the ice on the surface. No direct observations of Io's atmosphere in eclipse have previously been possible, due to the simultaneous need for high spectral and time sensitivity, as well as a high signal-to-noise ratio. Here we present the first ever high-resolution spectra at 19 µm of Io's SO2 atmosphere in Jupiter eclipse from the Gemini telescope. The strongest atmospheric band depth is seen to dramatically decay from 2.5 ± (0.08)% before the eclipse to 0.18 ± (0.16)% after 40 min in eclipse. Further modeling indicates that the atmosphere has collapsed shortly after eclipse ingress, implying that the atmosphere of Io has a strong sublimation-controlled component. The atmospheric column density—from pre-eclipse to in-eclipse—drops by a factor of 5 ± 2. ©2016. American Geophysical Union. All Rights Reserved.
Database: 
SCOPUS
ADS
URL: 
https://ui.adsabs.harvard.edu/#abs/2016JGRE..121.1400T/abstract
ADS Bibcode: 
2016JGRE..121.1400T
Keywords: 
atmosphere; ice sublimation; Io; volcanoes