Unexpected variability of Martian hydrogen escape

By M. Chaffin, J. Chaufray, I. Stewart, F. Montmessin, N. Schneider, Jean-Loup Bertaux. 2014

147 citations recorded by the source corpus.

Mars today is much drier than the Earth, though they likely began with similar relative amounts of water. One potential cause for this discrepancy is hydrogen loss to space, which may have removed a large fraction of Mars' initial water. Here we demonstrate an order‐of‐magnitude change in the Martian hydrogen escape rate in 2007, inconsistent with established models for the source of escaping hydrogen. We analyze 121.6 nm (hydrogen Lyman‐α) airglow observations made by the ultraviolet spectrometer on the Mars Express spacecraft over the second half of 2007. The enhanced escape rates we observe may be due to lower atmospheric heating and overturn during the 2007 (Mars Year 28) global dust storm, suggesting that hydrogen escape from Mars during dust storms may dominate loss of the planet's water inventory. This scenario has major implications for reconstructing the total amount of water lost to space over Martian history.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/fe3460c546d74068991b9d9bf20845b2bd30f070

How researchers see this paper

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In Astronomy and Astrophysics

1. J. Espley
2. R. Yelle
3. J. Clarke
4. J. Connerney
5. J. Mcfadden
6. B. Jakosky
7. F. Montmessin
8. F. Eparvier

Citations in the corpus

• Structure, dynamics, and seasonal variability of the Mars‐solar wind interaction: MAVEN Solar Wind Ion Analyzer in‐flight performance and science results (2017, background): “This decline most likely primarily reflects changes in the Martian exosphere, which we know to have a high degree of seasonal variability, thanks to spectroscopic observations [Chaffin et al., 2014; Bhattacharyya et al., 2015] and pickup ion measurements [Yamauchi et al., 2015].”
• The Imaging Ultraviolet Spectrograph (IUVS) for the MAVEN Mission (2015, background): “Studies of the hydrogen corona have already demonstrated that the loss of hydrogen to space through thermal escape (also known as Jeans escape; Chamberlain 1963) can be highly variable, driven either by dust storms below or other seasonal changes (Chaffin et al. 2014).”