Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published October 1, 1976 | public
Journal Article

Isotopic Composition of the Martian Atmosphere

Abstract

Results from the neutral mass spectrometer carried on the aeroshell of Viking 1 show evidence for NO in the upper atmosphere of Mars and indicate that the isotopic composition of carbon and oxygen is similar to that of Earth. Mars is enriched in ^(15)N relative to Earth by about 75 percent, a consequence of escape that implies an initial abundance of nitrogen equivalent to a partial pressure of at least 2 millibars. The initial abundance of oxygen present either as CO_2 or H_2O must be equivalent to an exchangeable atmospheric pressure of at least 2 bars in order to inhibit escape-related enrichment of ^(18)O.

Additional Information

© 1976 American Association for the Advancement of Science. Received 2 September 1976. Work at the University of Minnesota and at Harvard University was supported by NASA under contracts NAS-1-9697 and NAS-1-10492, respectively. A.O.N. is indebted to Ward Johnson for help in making computations.

Additional details

Created:
August 22, 2023
Modified:
October 26, 2023