A Stringent Upper Limit To SO2 In The Martian Atmosphere

dc.contributor.utaustinauthorLacy, J. H.en_US
dc.creatorEncrenaz, T.en_US
dc.creatorGreathouse, T. K.en_US
dc.creatorRichter, M. J.en_US
dc.creatorLacy, J. H.en_US
dc.creatorFouchet, T.en_US
dc.creatorBezard, B.en_US
dc.creatorLefevre, F.en_US
dc.creatorForget, F.en_US
dc.creatorAtreya, S. K.en_US
dc.description.abstractSurfur-bearing molecules have been found at the surface of Mars by the Viking lander, the Spirit and Opportunity rovers, and the OMEGA infrared spectrometer aboard Mars Express. However, no gaseous sulfur-bearing species have ever been detected in the Martian atmosphere. We search for SO2 signatures in the thermal spectrum of Mars at 7.4 mu m using the Texas Echelon Cross Echelle Spectrograph (TEXES) at the NASA Infrared Telescope Facility (IRTF). Data were obtained on Oct. 12, 2009 (Ls = 353 degrees), in the 1350-1360 cm(-1) range, with a spatial resolution of 1 arcsec (after convolution over three pixels along the N-S axis and two steps along the E-W axis) and a resolving power of 80 000. To improve the signal-to-noise ratio (S/N), we co-added the Martian spectrum around the positions of nine selected SO2 transitions with a high S/N and no telluric contamination. From a mean spectrum, averaged over 35 pixels in the region of maximum continuum, we infer a 2 sigma upper limit of 0.3 ppb to the SO2 mixing ratio, assuming that our instrumental errors are combined according to Gaussian statistics. Our upper limit is three times lower than the upper limit derived by Krasnopolsky (2005, Icarus, 178, 487), who used the same technique on previous TEXES data. In addition, we derive an upper limit of 2 ppb at each spatial pixel of the region observed by TEXES, which covers the longitude ranges 50 E-170 E for latitudes above 30 N, 100 E-170 E for latitudes between 0 and 30 N, and 110 E-170 E for latitudes between 15 S and 0. The non-detection of localized SO2 sources in the observed area is consistent with a homogeneous distribution being expected around equinox for non-condensible species with a lifetime longer than the global mixing time. In view of the typically large SO2/CH4 ratio observed in terrestrial volcanoes, and assuming a comparable volcanic composition for Mars and the Earth, our result reaffirms that a volcanic origin is unlikely for any methane in the Martian atmosphere.en_US
dc.description.sponsorshipNSF AST-0607312, AST-0708074en_US
dc.description.sponsorshipNASA NNX08AW33G S03en_US
dc.identifier.citationEncrenaz, Th, T. K. Greathouse, M. J. Richter, J. H. Lacy, T. Fouchet, B. Bézard, Franck Lefèvre, F. Forget, and S. K. Atreya. >A stringent upper limit to SO2 in the martian atmosphere.> Astronomy & Astrophysics, Vol. 530 (Jun., 2011): A37.en_US
dc.relation.ispartofserialAstronomy & Astrophysicsen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.subjectplanets and satellites: atmospheresen_US
dc.subjectinfrared: planetary systemsen_US
dc.subjectplanets and satellites: individual: marsen_US
dc.subjectimaging spectroscopyen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleA Stringent Upper Limit To SO2 In The Martian Atmosphereen_US

Access full-text files

Original bundle

Now showing 1 - 1 of 1
Thumbnail Image
299.01 KB
Adobe Portable Document Format