A comparison of 3‐D model predictions of Mars' oxygen corona with early MAVEN IUVS observations

Lee, Yuni; Combi, M. R.; Tenishev, V.; Bougher, S. W.; Deighan, Justin; Schneider, Nicholas M.; McClintock, W. E.; Jakosky, B. M.

doi:10.1002/2015gl065291

Cited by 40 publications

(67 citation statements)

References 31 publications

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“…Gröller et al [], however, have shown that dissociative recombination of

{CO}_{2}^{+}

also plays an important role in producing hot oxygen atoms in the present Martian atmosphere. This finding was recently confirmed by Lee et al []. In the present work, we extend the study of Zhao and Tian [] by including more source reactions for hot oxygen and by including hot carbon, since both species are connected to the loss of CO 2 throughout the Martian evolution.…”

Section: Introductionsupporting

confidence: 79%

Escape and evolution of Mars's CO₂ atmosphere: Influence of suprathermal atoms

et al. 2017

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With a Monte Carlo model we investigate the escape of hot oxygen and carbon from the Martian atmosphere for four points in time in its history corresponding to 1, 3, 10, and 20 times the present solar EUV flux. We study and discuss different sources of hot oxygen and carbon atoms in the thermosphere and their changing importance with the EUV flux. The increase of the production rates due to higher densities resulting from the higher EUV flux competes against the expansion of the thermosphere and corresponding increase in collisions. We find that the escape due to photodissociation increases with increasing EUV level. However, for the escape via some other reactions, e.g., dissociative recombination of O2+, this is only true until the EUV level reaches 10 times the present EUV flux and then the rates start to decrease. Furthermore, our results show that Mars could not have had a dense atmosphere at the end of the Noachian epoch, since such an atmosphere would not have been able to escape until today. In the pre‐Noachian era, most of the magma ocean and volcanic activity‐related outgassed CO2 atmosphere could have been lost thermally until the Noachian epoch, when nonthermal loss processes such as suprathermal atom escape became dominant. Thus, early Mars could have been hot and wet during the pre‐Noachian era with surface CO2 pressures larger than 1 bar during the first 300 Myr after the planet's origin.

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“…Gröller et al [], however, have shown that dissociative recombination of

{CO}_{2}^{+}

Section: Introductionsupporting

confidence: 79%

Escape and evolution of Mars's CO₂ atmosphere: Influence of suprathermal atoms

et al. 2017

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“…This value is consistent with non-thermal oxygen atoms being produced by dissociative recombination of O 2 + (equation (1a)- (1e)) and undergoing a small number of collisions before reaching the exosphere. Agreement in slope between predicted and IUVS observed brightness profiles has also been found in a preliminary comparison using the detailed M-AMPS model [Lee et al, 2015].…”

Section: 1002/2015gl065487mentioning

confidence: 70%

MAVEN IUVS observation of the hot oxygen corona at Mars

Deighan

Chaffin

Chaufray

et al. 2015

Geophysical Research Letters

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Observation of the hot oxygen corona at Mars has been an elusive measurement in planetary science. Characterizing this component of the planet's exosphere provides insight into the processes driving loss of oxygen at the current time, which informs understanding of the planet's climatic evolution. The Mars Atmosphere and Volatile EvolutioN (MAVEN) Imaging Ultraviolet Spectrograph (IUVS) instrument is now regularly collecting altitude profiles of the hot oxygen corona as part of its investigation of atmospheric escape from Mars. Observations obtained thus far have been examined and found to display the expected gross structure and variability with EUV forcing anticipated by theory. The quality and quantity of the data set provides valuable constraints for the coronal modeling community.

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“…DR of CO 2 + , which is another nonnegligible source of hot O suggested by Gröller et al [], is not included in this study, since the introduction of a new source is beyond the scope of this study. However, the contribution from DR of CO 2 + to the hot O corona for a particular seasonal and solar activity case has been compared with the observations by Imaging Ultraviolet Spectrograph/MAVEN in Lee et al [].…”

Section: Modelsmentioning

confidence: 99%

Hot oxygen corona at Mars and the photochemical escape of oxygen: Improved description of the thermosphere, ionosphere, and exosphere

Lee

Combi

Tenishev

et al. 2015

J. Geophys. Res. Planets

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The Mars Adaptive Mesh Particle Simulator model is coupled with the Mars Global Ionosphere Thermosphere Model for the first time to provide an improved description of the Martian hot O corona based on our modeling studies of O2+ dissociative recombination. A total of 12 cases comprising three solar activity levels and four orbital positions is considered to study the solar cycle and seasonal variability. The newly coupled framework includes two additional thermospheric species and adopts a realistic forward scattering scheme using the angular differential cross sections. We present the effects of these changes on the resulting hot O corona and escape rate. A comparison between the simulated hot O corona and the recent observations from the ALICE/Rosetta instrument showed a reasonable agreement, considering the large uncertainties in the data. We assume that some discrepancies near the transition altitude may be originated from the averaging over the altitude range, where the cold and hot O densities become comparable. The revised O escape rates by our new coupled framework range from ~1.21 × 1025 s−1 to ~5.43 × 1025 s−1.

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A comparison of 3‐D model predictions of Mars' oxygen corona with early MAVEN IUVS observations

Cited by 40 publications

References 31 publications

Escape and evolution of Mars's CO₂ atmosphere: Influence of suprathermal atoms

Escape and evolution of Mars's CO₂ atmosphere: Influence of suprathermal atoms

MAVEN IUVS observation of the hot oxygen corona at Mars

Hot oxygen corona at Mars and the photochemical escape of oxygen: Improved description of the thermosphere, ionosphere, and exosphere

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A comparison of 3‐D model predictions of Mars' oxygen corona with early MAVEN IUVS observations

Cited by 40 publications

References 31 publications

Escape and evolution of Mars's CO2 atmosphere: Influence of suprathermal atoms

Escape and evolution of Mars's CO2 atmosphere: Influence of suprathermal atoms

MAVEN IUVS observation of the hot oxygen corona at Mars

Hot oxygen corona at Mars and the photochemical escape of oxygen: Improved description of the thermosphere, ionosphere, and exosphere

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Escape and evolution of Mars's CO₂ atmosphere: Influence of suprathermal atoms

Escape and evolution of Mars's CO₂ atmosphere: Influence of suprathermal atoms