Loss of hydrogen and oxygen from the upper atmosphere of Venus

Lämmer, H.; Lichtenegger, Herbert; Biernat, H. K.; Еркаев, Н. В.; Arshukova, I. L.; Kolb, C.; Gunell, H.; Lukyanov, A.; Holmström, M.; Barabash, S.; Zhang, T.L.; Baumjohann, W.

doi:10.1016/j.pss.2006.04.022

Cited by 108 publications

(117 citation statements)

References 84 publications

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“…In recent studies by Kulikov et al (2006Kulikov et al ( , 2007, Lammer et al (2006Lammer et al ( , 2008, Lundin et al (2007), Tian et al (2008a, b) and illustrated in Fig. 4 it was shown that enhanced solar EUV radiation and plasma (winds, CMEs) should result in permanent forcing of the upper planetary atmospheres, which can ionize, heat, expand, chemically modify, and erode it during the early phase of a planetary lifetime.…”

Section: Solar Activity Response Of Planetary Upper Atmospheresmentioning

confidence: 96%

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Variability of solar/stellar activity and magnetic field and its influence on planetary atmosphere evolution

et al. 2012

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It is shown that the evolution of planetary atmospheres can only be understood if one recognizes the fact that the radiation and particle environment of the Sun or a planet's host star were not always on the same level as at present. New insights and the latest observations and research regarding the evolution of the solar radiation, plasma environment and solar/stellar magnetic field derived from the observations of solar proxies with different ages will be given. We show that the extreme radiation and plasma environments of the young Sun/stars have important implications for the evolution of planetary atmospheres and may be responsible for the fact that planets with low gravity like early Mars most likely never build up a dense atmosphere during the first few 100 Myr after their origin. Finally we present an innovative new idea on how hydrogen clouds and energetic neutral atom (ENA) observations around transiting Earth-like exoplanets by space observatories such as the WSO-UV, can be used for validating the addressed atmospheric evolution studies. Such observations would enhance our understanding on the impact on the activity of the young Sun on the early atmospheres of Venus, Earth, Mars and other Solar System bodies as well as exoplanets.

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Section: Solar Activity Response Of Planetary Upper Atmospheresmentioning

confidence: 96%

“…Nagy et al, 1981;Lammer and Bauer, 1991;Kim et al, 1998;Hodges, 2000;Krestyanikova and Shematovich, 2006;Lammer et al, 2006;Gröller et al, 2010;Valeille et al, 2010). For H 2 , radiation λ < 850Å leads to either dissociation or ionization.…”

Section: The Moderate Activity Period: Solar Radiation Plasma and Mamentioning

confidence: 99%

Variability of solar/stellar activity and magnetic field and its influence on planetary atmosphere evolution

et al. 2012

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“…There are no estimates for Earth in the literature since sputtering is prevented by the magnetic field. We have used the Venus sputtering escape rate (Luhmann & Kozyra 1991;Lammer et al 2006) also for Earth, because Earth and Venus are similar in size, mass, and exosphere temperature.…”

Section: A25 Sputteringmentioning

confidence: 99%

Why an intrinsic magnetic field does not protect a planet against atmospheric escape

Gunell

Maggiolo

Nilsson

et al. 2018

A&A

108

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The presence or absence of a magnetic field determines the nature of how a planet interacts with the solar wind and what paths are available for atmospheric escape. Magnetospheres form both around magnetised planets, such as Earth, and unmagnetised planets, like Mars and Venus, but it has been suggested that magnetised planets are better protected against atmospheric loss. However, the observed mass escape rates from these three planets are similar (in the approximate (0.5−2) kg s −1 range), putting this latter hypothesis into question. Modelling the effects of a planetary magnetic field on the major atmospheric escape processes, we show that the escape rate can be higher for magnetised planets over a wide range of magnetisations due to escape of ions through the polar caps and cusps. Therefore, contrary to what has previously been believed, magnetisation is not a sufficient condition for protecting a planet from atmospheric loss. Estimates of the atmospheric escape rates from exoplanets must therefore address all escape processes and their dependence on the planet's magnetisation.

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“…The most crucial processes are related to ion pick-up, sputtering, ionospheric outflow, and also dissociative recombination; the ionizing source for the upper planetary atmosphere is the EUV and X-ray emission from the Sun (for a summary see, e.g., Chassefière & Leblanc 2004, and Lundin et al 2007. These processes are thought to have fundamentally altered the atmospheres 382 M. Güdel of Venus, Earth, and Mars, leading to strong loss of oxygen (Lammer et al 2006) and therefore water (after photodissociation of water vapor in the upper atmosphere) from young Venus and Mars. A strong magnetosphere around the Earth, shielding the lower atmospheric layers, may have been instrumental in retaining much of its water and making it habitable.…”

Section: High-energy Radiation and The Stellar Environmentmentioning

confidence: 99%

Magnetic activity, high-energy radiation and variability: from young solar analogs to low-mass objects

Güdel

2009

Proc. IAU

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Abstract. Magnetic activity on cool stars expresses itself in a bewildering variety of radiative and particle output originating from magnetic regions between the photosphere and the corona. Given its origin in evolving magnetic fields, most of this output is variable in time. Radiation in the ultraviolet, the extreme ultraviolet, and the X-ray ranges are important for heating and ionizing upper planetary atmospheres and thus driving atmospheric evaporation. Additionally, stellar winds interact with the upper atmospheres and may lead to further erosion. The stellar high-energy output is therefore a prime factor in determining habitability of planets. We summarize our knowledge of magnetic activity in young solar analogs and lower-mass stars and show how the stellar output changes on evolutionary timescales.

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Loss of hydrogen and oxygen from the upper atmosphere of Venus

Cited by 108 publications

References 84 publications

Variability of solar/stellar activity and magnetic field and its influence on planetary atmosphere evolution

Variability of solar/stellar activity and magnetic field and its influence on planetary atmosphere evolution

Why an intrinsic magnetic field does not protect a planet against atmospheric escape

Magnetic activity, high-energy radiation and variability: from young solar analogs to low-mass objects

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