Lyman-alpha observations of venera-9 and 10 I. The non-thermal hydrogen population in the exosphere of venus

Bertaux, I.L.; Blamont, J. É.; Marcelin, M.; Kurt, V. G.; Romanova, N. N.; Смирнов, А. С.

doi:10.1016/0032-0633(78)90105-8

Cited by 45 publications

(14 citation statements)

References 15 publications

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“…The Venusian profile presents two scale heights corresponding to a cold hydrogen population dominant below 2000 km (∼1.3 Rv; where Rv is the Venus radius of 6051 km) and a hot hydrogen population dominant above 4000 (∼1.7 Rv) km. These two scale height profiles have already been observed by several previous missions to Venus (Anderson 1976;Bertaux et al 1978Bertaux et al , 1982Takacs et al 1980;Paxton et al 1988). On Mars, the Lyman-α brightness profile is rather constant between 400 km and 1000 km (1.2-1.4 Rm).…”

Section: Recent Observations Of Hydrogen Coronae By Uv Remote Sensingsupporting

confidence: 52%

Exospheres and Energetic Neutral Atoms of Mars, Venus and Titan

et al. 2011

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International audienceOur understanding of the upper atmosphere of unmagnetized bodies such as Mars, Venus and Titan has improved significantly in this decade. Recent observations by in situ and remote sensing instruments on board Mars Express, Venus Express and Cassini have revealed characteristics of the neutral upper atmospheres (exospheres) and of energetic neutral atoms (ENAs). The ENA environment in the vicinity of the bodies is by itself a significant study field, but ENAs are also used as a diagnostic tool for the exosphere and the interaction with the upstream plasmas. Synergy between theoretical and modeling work has also improved considerably. In this review, we summarize the recent progress of our understanding of the neutral environment in the vicinity of unmagnetized planets

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Section: Recent Observations Of Hydrogen Coronae By Uv Remote Sensingsupporting

confidence: 52%

Exospheres and Energetic Neutral Atoms of Mars, Venus and Titan

et al. 2011

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“…Bertaux et al (1978) analyzed the data obtained using a spherically-symmetric, isothermal radiative transfer model. They found that the data could be fit by a two-temperature model, but the fit was not better than that of a one-temperature model at 500 K with an exobase density of 1.5 x 104 cm-3, values which are bracketed by those of the hot and cold components from the Mariner 5 and 10 analyses.…”

Section: H and H 2 Densitiesmentioning

confidence: 99%

“…Donahue found that a predicted intensity of 1.0 + 0.4 kR is more appropriate and that the upper limit implied by 300 kR ofD L~is about 5 x 10 -3. Bertaux and Clarke (1989b) suggest that the larger D/H ratio measured by Donahue et al (1982) should produce observable limb brightening of the D Le emission and that a search of the data collected by the PV OUVS should reveal such a limb brightening.…”

Section: D/h Ratiomentioning

confidence: 99%

“…They constructed a 3-D (nonspherically symmetric) Monte-Carlo model of the Venus densities and temperatures, and found that the most important source is the charge exchange from H +, with charge exchange from O + contributing only near the exobase. They criticized the hot H source proposed by Bertaux et al (1978), charge exchange from solar wind protons, as requiring the deceleration of solar wind neutralized protons from 400 km s-1 to sub-escape speeds and concluded that the magnitude of this source of hot H was negligible. The charge exchange sources adequately reproduced the day/night ratios of the hot H concentrations and scale heights.…”

Section: Models Of Hot and Escaping Hydrogenmentioning

confidence: 99%

“…The Venera 9 and 10 orbiters also visited the planet in October 1975 through February 1976. Remote Le (Bertaux et al, 1978) and visible airglow (Krasnopolsky et al, 1976) observations were made (Flo7 = 75). No definitive estimate of neutral temperatures could, however, be derived.…”

Section: Solar Cycle Variationmentioning

confidence: 99%

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Structure, luminosity, and dynamics of the Venus thermosphere

Fox

Bougher

1991

Space Sci Rev

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We review here observations and models related to the chemical and thermal structures, airglow and auroral emissions and dynamics of the Venus thermosphere, and compare empirical models of the neutral densities based in large part on in situ measurements obtained by the Pioneer Venus spacecraft.Observations of the intensities of emissions are important as a diagnostic tool for understanding the chemical and physical processes taking place in the Venus thermosphere. Measurements, ground-based and from rockets, satellites, and spacecraft, and model predictions of atomic, molecular and ionic emissions, are presented and the most important sources are elucidated. Coronas of hot hydrogen and hot oxygen have been observed to surround the terrestrial planets. We discuss the observations of and production mechanisms for the extended exospheres and models for the escape of lighter species from the atmosphere. Over the last decade and a half, models have attempted to explain the unexpectedly cold temperatures in the Venus thermosphere; recently considerable progress has been made, although some controversies remain. We review the history of these models and discuss the heating and cooling mechanisms that are presently considered to be the most important in determining the thermal structure. Finally, we discuss major aspects of the circulation and dynamics of the thermosphere: the sub-solar to anti-solar circulation, superrotation, and turbulent processes.

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