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Abundance and Isotopic Composition of Gases in the Martian Atmosphere: First Results from the Mars Curiosity RoverRepeated measurements of the composition of the Mars atmosphere from Curiosity Rover yield a (40)Ar/N2 ratio 1.7 times greater and the (40)Ar/(36)Ar ratio 1.6 times smaller than the Viking Lander values in 1976. The unexpected change in (40)Ar/N2 ratio probably results from different instrument characteristics although we cannot yet rule out some unknown atmospheric process. The new (40)Ar/(36)Ar ratio is more aligned with Martian meteoritic values. Besides Ar and N2 the Sample Analysis at Mars instrument suite on the Curiosity Rover has measured the other principal components of the atmosphere and the isotopes. The resulting volume mixing ratios are: CO2 0.960(+/- 0.007); (40)Ar 0.0193(+/- 0.0001); N2 0.0189(+/- 0.0003); O2 1.45(+/- 0.09) x 10(exp -3); and CO 5.45(+/- 3.62) x 10(exp 4); and the isotopes (40)Ar/(36)Ar 1.9(+/- 0.3) x 10(exp 3), and delta (13)C and delta (18)O from CO2 that are both several tens of per mil more positive than the terrestrial averages. Heavy isotope enrichments support the hypothesis of large atmospheric loss. Moreover, the data are consistent with values measured in Martian meteorites, providing additional strong support for a Martian origin for these rocks.
Document ID
Document Type
Preprint (Draft being sent to journal)
Mahaffy, Paul
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Webster, Chris R.
(Jet Propulsion Laboratory)
Atreya, Sushil K.
(Michigan Univ. Ann Arbor, MI, United States)
Franz, Heather
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Wong, Michael
(Michigan Univ. Ann Arbor, MI, United States)
Conrad, Pamela G.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Harpold, Dan
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Jones, John J.
(NASA Johnson Space Center Houston, TX, United States)
Leshin, Laurie, A.
(Rensselaer Polytechnic Inst. Troy, NY, United States)
Manning, Heidi
(Concordia Coll. Moorhead, MN, United States)
Owen, Tobias
(Hawaii Univ. Honolulu, HI, United States)
Pepin, Robert O.
(Minnesota Univ. Minneapolis, MN, United States)
Squyres, Steven
(Cornell Univ., Inc. Ithaca, NY, United States)
Trainer, Melissa
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
February 3, 2015
Publication Date
January 1, 2013
Publication Information
Publisher: AAAS
Subject Category
Inorganic, Organic And Physical Chemistry
Lunar And Planetary Science And Exploration
Report/Patent Number
Distribution Limits
Public Use Permitted.
Results from Curiosity
Isotopic Gases
Curiosity Rover
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