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Upper limits on argon isotope abundances in the Venus thermosphere
Author(s) -
Mauersberger K.,
Zahn U.,
Krankowsky D.
Publication year - 1979
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl006i008p00671
Subject(s) - thermosphere , venus , atmosphere of venus , altitude (triangle) , argon , troposphere , mixing ratio , atmosphere (unit) , atmospheric sciences , isotopes of argon , isotope , physics , ionosphere , astrobiology , atomic physics , meteorology , astronomy , nuclear physics , geometry , mathematics
On December 9, 1978 the neutral gas mass spectrometer aboard the NASA Pioneer Venus multiprobe bus has measured density, composition, and temperature of the Venus dayside thermosphere. There was no positive identification of argon down to the lowest measuring altitude of 130 km. For the altitude level of 135 km the following upper limits for the number densities of argon isotopes were derived: n( 36 Ar) < 1.3 × 10 6 cm −3 and n( 40 Ar) < 2.8 × 10 6 cm −3 . From our upper atmosphere observations we infer for the troposphere of Venus the following upper limits for the mixing ratios: n( 36 Ar)/total number density < 9 × 10 −6 and n( 40 Ar)/total number density < 20 × 10 −6 .