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Science 6 July 1979:
Vol. 205. no. 4401, pp. 54 - 56
DOI: 10.1126/science.205.4401.54
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Articles

Venus Upper Atmosphere Neutral Gas Composition: First Observations of the Diurnal Variations

H. B. NIEMANN 1, R. E. HARTLE 1, A. E. HEDIN 1, W. T. KASPRZAK 1, N. W. SPENCER 1, D. M. HUNTEN 2, and G. R. CARIGNAN 3

1 Laboratory for Planetary Atmospheres, NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771
2 Lunar and Planetary Laboratory, Univerity of Arizona, Tucson 85721
3 Space Physics Research Laboratory, University of Michigan, Ann Arbor 48105

Measurements of the composition, temperature, and diurnal variations of the major neutral constituents in the thermosphere of Venus are being made with a quadrupole mass spectrometer on the Pioneer Venus orbiter. Concentrations of carbon dioxide, carbon monoxide, molecular nitrogen, atomic oxygen, and helium are presented, in addition to an empirical model of the data. The concentrations of the heavy gases, carbon dioxide, carbon monoxide, and molecular nitrogen, rapidly decrease from the evening terminator toward the nightside; the concentration of atomic oxygen remains nearly constant and the helium concentration increases, an indication of a nightside bulge. The kinetic temperature inferred from scale heights drops rapidly from 230 K at the terminator to 130 K at a solar zenith angle of 120°, and to 112 K at the antisolar point.

Submitted on May 15, 1979


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Ultraviolet Night Airglow of Venus.
A. I. STEWART and C. A. BARTH (1979)
Science 205, 59-62
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Ionosphere of Venus: First Observations of Day-Night Variations of the Ion Composition.
H. A. TAYLOR JR., H. C. BRINTON, S. J. BAUER, R. E. HARTLE, P. A. CLOUTIER, R. E. DANIELL JR., and T. M. DONAHUE (1979)
Science 205, 96-99
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Initial Observations of the Nightside Ionosphere of Venus from Pioneer Venus Orbiter Radio Occultations.
A. J. KLIORE, I. R. PATEL, A. F. NAGY, T. E. CRAVENS, and T. I. GOMBOSI (1979)
Science 205, 99-102
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Empirical Models of the Electron Temperature and Density in the Nightside Venus Ionosphere.
L. H. BRACE, R. F. THEIS, H. B. NIEMANN, H. G. MAYR, W. R. HOEGY, and A. F. NAGY (1979)
Science 205, 102-105
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Thermal Structure and Energy Influx to the Day-and Nightside Venus Ionosphere.
W. C. KNUDSEN, K. SPENNER, R. C. WHITTEN, J. R. SPREITER, K. L. MILLER, and V. NOVAK (1979)
Science 205, 105-107
   Abstract »    PDF »
Venus Ionosphere: Photochemical and Thermal Diffusion Control of Ion Composition.
S. J. BAUER, T. M. DONAHUE, R. E. HARTLE, and H. A. TAYLOR JR. (1979)
Science 205, 109-112
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