Isotopes of nitrogen on Mars: Atmospheric measurements by Curiosity's mass spectrometer

Michael H Wong; Sushil K Atreya; Paul N Mahaffy; Heather B Franz; Charles Malespin; Melissa G Trainer; Jennifer C Stern; Pamela G Conrad; Heidi L K Manning; Robert O Pepin; Richard H Becker; Christopher P McKay; Tobias C Owen; Rafael Navarro-González; John H Jones; Bruce M Jakosky; Andrew Steele

doi:10.1002/2013GL057840

Isotopes of nitrogen on Mars: Atmospheric measurements by Curiosity's mass spectrometer

Geophys Res Lett. 2013 Dec 16;40(23):6033-6037. doi: 10.1002/2013GL057840. Epub 2013 Dec 9.

Authors

Michael H Wong¹, Sushil K Atreya², Paul N Mahaffy³, Heather B Franz³, Charles Malespin³, Melissa G Trainer³, Jennifer C Stern³, Pamela G Conrad³, Heidi L K Manning⁴, Robert O Pepin⁵, Richard H Becker⁵, Christopher P McKay⁶, Tobias C Owen⁷, Rafael Navarro-González⁸, John H Jones⁹, Bruce M Jakosky¹⁰, Andrew Steele¹¹

Affiliations

¹ Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan Ann Arbor, Michigan, USA ; Astronomy Department, University of California Berkeley, California, USA.
² Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan Ann Arbor, Michigan, USA.
³ Code 699, NASA Goddard Space Flight Center Greenbelt, Maryland, USA.
⁴ Department of Physics, Concordia College Moorhead, Minnesota, USA.
⁵ School of Physics and Astronomy, University of Minnesota Minneapolis, Minnesota, USA.
⁶ NASA Ames Research Center Moffet Field, California, USA.
⁷ Institute for Astronomy, University of Hawai'i at Mānoa Honolulu, Hawaii, USA.
⁸ Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México México City, México.
⁹ NASA Johnson Space Center Houston, Texas, USA.
¹⁰ LASP, University of Colorado Boulder Colorado, USA.
¹¹ Geophysical Laboratory, Carnegie Institution of Washington Washington, District of Columbia, USA.

Abstract

[1] The Sample Analysis at Mars (SAM) instrument suite on the Mars Science Laboratory (MSL) measured a Mars atmospheric¹⁴N/¹⁵N ratio of 173 ± 11 on sol 341 of the mission, agreeing with Viking's measurement of 168 ± 17. The MSL/SAM value was based on Quadrupole Mass Spectrometer measurements of an enriched atmospheric sample, with CO₂ and H₂O removed. Doubly ionized nitrogen data at m/z 14 and 14.5 had the highest signal/background ratio, with results confirmed by m/z 28 and 29 data. Gases in SNC meteorite glasses have been interpreted as mixtures containing a Martian atmospheric component, based partly on distinctive¹⁴N/¹⁵N and⁴⁰Ar/¹⁴N ratios. Recent MSL/SAM measurements of the⁴⁰Ar/¹⁴N ratio (0.51 ± 0.01) are incompatible with the Viking ratio (0.35 ± 0.08). The meteorite mixing line is more consistent with the atmospheric composition measured by Viking than by MSL.