A new search for active release of volcanic gases on Mars: Sensitive upper limits for OCS.
Abstract
As part of our multi-species search for active release of volcanic gases on Mars, we looked for atmospheric carbonyl sulfide (OCS) in two successive Mars years (31 & 32), during Mars’ late Northern Spring and mid Northern Summer seasons, between Ls= 43° and Ls= 147°. The targeted volcanic districts, Tharsis and Syrtis Major, were observed during the two intervals, 14 Dec. 2011 to 6 Jan. 2012 on the first year, and 30 May 2014 to 16 June 2014 on the second year using the high resolution infrared spectrometer (CSHELL) on NASA’s Infrared Telescope Facility (NASA/IRTF) atop Maunakea, Hawaii. On Earth, sulfur dioxide (SO2) and hydrogen sulfide (H2S) are the main sulfur species released during volcanic outgassing. The two molecules have relatively short photochemical lifetimes on Mars, 2 years for SO2 (Krasnopolsky, 1995; Nair et al., 1994) and 9 days for H2S (Wong et al., 2003), and OCS is a byproduct of the photochemical cycle. With an 850 km spatial resolution on Mars, we positioned CSHELL’s slit at the North-South central meridian of the planet above each volcanic region, and searched for OCS, both in its combination band (ν2+ν3) at 3.42 μm and its fundamental band (ν3) centered at 4.85 μm. OCS was not detected, and sensitive upper limits will be presented. The non-detection of measurable OCS quantities in the atmosphere of Mars indicates the absence of major volcanic outgassing, and provides limits for the level of current volcanic activity in the crust of Mars. Those limits will be discussed. We gratefully acknowledge support from the NASA Planetary Astronomy Program under Cooperative Agreement NNX08AE38A that supported A.J.K., and A.T.T., RTOP 344-32-07 and NASA’s Astrobiology Program (RTOP 344-53-51) that supported M.J.M., and G.L.V.
- Publication:
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AAS/Division for Planetary Sciences Meeting Abstracts #46
- Pub Date:
- November 2014
- Bibcode:
- 2014DPS....4641204K