The upper atmosphere of Venus: Model predictions for mass spectrometry measurements

Gruchola, Salome; Galli, André; Vorburger, Audrey; Würz, Peter

doi:10.1016/j.pss.2019.03.006

Cited by 8 publications

(7 citation statements)

References 42 publications

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“…First, hydrogen is a trace species in rocky planet atmospheres, so the formation of phosphine is not favored as it is in the deep atmospheres of the H2-dominated giant planets. On Earth H2 reaches 0.55 ppm levels (Novelli et al 1999), on Venus it is much lower at ~4 ppb (Gruchola et al 2019;Krasnopolsky 2010). Second, rocky planet atmospheres do not extend to a depth where, even if their atmosphere were composed primarily of hydrogen, phosphine formation would be favored (the possibility that phosphine can be formed below the surface and then being erupted out of volcanoes is addressed separately in Section 3.2.2 and Section 3.2.3, but is also highly unlikely).…”

Section: Detection Of Phosphine On Venus and Other Planetsmentioning

confidence: 97%

Phosphine on Venus Cannot Be Explained by Conventional Processes

et al. 2021

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The recent candidate detection of ~20 ppb of phosphine in the middle atmosphere of Venus is so unexpected that it requires an exhaustive search for explanations of its origin. Phosphoruscontaining species have not been modelled for Venus' atmosphere before and our work represents the first attempt to model phosphorus species in Venusian atmosphere. We thoroughly explore the potential pathways of formation of phosphine in a Venusian environment, including in the planet's atmosphere, cloud and haze layers, surface, and subsurface. We investigate gas reactions, geochemical reactions, photochemistry, and other non-equilibrium processes. None of these potential phosphine production pathways are sufficient to explain the presence of ppb phosphine levels on Venus. The presence of PH3, therefore, must be the result of a process not previously considered plausible for Venusian conditions. The process could be unknown geochemistry, photochemistry, or even aerial microbial life, given that on Earth phosphine is exclusively associated with anthropogenic and biological sources. The detection of phosphine adds to the complexity of chemical processes in the Venusian environment and motivates in situ follow up sampling missions to Venus.

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Section: Detection Of Phosphine On Venus and Other Planetsmentioning

confidence: 97%

Phosphine on Venus Cannot Be Explained by Conventional Processes

et al. 2021

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“…Ar + + CO 2 reaction is of importance in the ionospheres of Mars and Venus, where CO 2 is the most abundant neutral species and there are a few Ar atoms. , As indicated by Fehsenfeld, the recombination of electrons with molecular ions is more efficient in many orders of magnitude than those with atomic ions. The molecular ions formed via the charge exchange reactions with the atomic ions are also involved in the recombination reactions, which is a non-negligible factor to control the electron density in planetary ionospheres.…”

Section: Introductionmentioning

confidence: 99%

Ion Momentum Imaging Study of the Ion–Molecule Charge Exchange Reaction of Ar⁺ + CO₂

et al. 2019

J. Phys. Chem. A

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Three-dimensional ion momentum imaging is developed in a combination of ion velocity map imaging technique and delay-line anode ion detection, and it is applied for the ion−molecule charge exchange reaction between Ar + and CO 2 . In a center-of-mass collision energy range of 7.23−15.96 eV, CO 2 + products are primarily populated at the ground state X 2 Π g and the single-electron excited states A 2 Π u , B 2 Σ u + , and C 2 Σ g + ; the multielectron excited states of CO 2 + are also found at the higher collision energies. The production efficiency profiles of CO 2 + are distinctly different from the photoionization electron spectrum of CO 2 , implying that the charge transfer from Ar + would be not fast as expected. The strong electron correlations in the short-lived intermediate (Ar−CO 2 ) + should be responsible for the CO 2 + yields at the multielectron excited states.

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“…In situ investigations at low velocity and well below the homopause ensure that the measured gas is representative of the entire atmosphere and that detected abundances and ratios are unambiguous (Tian, 2015). Deep atmosphere sam-pling also avoids any uncertainties introduced by temporal or spatial variability of the homopause location by species or other upper atmosphere stratification (von Zahn et al, 1980;Mahieux et al, 2012;Gruchola et al, 2019;Peplowski et al, 2020).…”

Section: In Situ Measurementsmentioning

confidence: 98%

“…Deep atmosphere sampling also avoids any uncertainties introduced by temporal or spatial Fig. 10 The NASA DAVINCI mission (Garvin et al 2022) will conduct in situ sampling of the Venus atmosphere during its ≈hour-long descent to the surface, providing critical measurements of noble gases and stable isotopes variability of the homopause location by species or other upper atmosphere stratification (von Zahn et al 1980;Mahieux et al 2012;Gruchola et al 2019;Peplowski et al 2020).…”

Section: In Situ Measurementsmentioning

confidence: 99%

Noble Gases and Stable Isotopes Track the Origin and Early Evolution of the Venus Atmosphere

et al. 2022

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The composition the atmosphere of Venus results from the integration of many processes entering into play over the entire geological history of the planet. Determining the elemental abundances and isotopic ratios of noble gases (He, Ne, Ar, Kr, Xe) and stable isotopes (H, C, N, O, S) in the Venus atmosphere is a high priority scientific target since it could open a window on the origin and early evolution of the entire planet. This chapter provides an overview of the existing dataset on noble gases and stable isotopes in the Venus atmosphere. The current state of knowledge on the origin and early and long-term evolution of the Venus atmosphere deduced from this dataset is summarized. A list of persistent and new unsolved scientific questions stemming from recent studies of planetary atmospheres (Venus, Earth and Mars) are described. Important mission requirements pertaining to the measurement of volatile elements in the atmosphere of Venus as well as potential technical difficulties are outlined.

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The upper atmosphere of Venus: Model predictions for mass spectrometry measurements

Cited by 8 publications

References 42 publications

Phosphine on Venus Cannot Be Explained by Conventional Processes

Phosphine on Venus Cannot Be Explained by Conventional Processes

Ion Momentum Imaging Study of the Ion–Molecule Charge Exchange Reaction of Ar⁺ + CO₂

Noble Gases and Stable Isotopes Track the Origin and Early Evolution of the Venus Atmosphere

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The upper atmosphere of Venus: Model predictions for mass spectrometry measurements

Cited by 8 publications

References 42 publications

Phosphine on Venus Cannot Be Explained by Conventional Processes

Phosphine on Venus Cannot Be Explained by Conventional Processes

Ion Momentum Imaging Study of the Ion–Molecule Charge Exchange Reaction of Ar+ + CO2

Noble Gases and Stable Isotopes Track the Origin and Early Evolution of the Venus Atmosphere

Contact Info

Product

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Ion Momentum Imaging Study of the Ion–Molecule Charge Exchange Reaction of Ar⁺ + CO₂