Effects of magnetic fields on the location of the evaporation valley for low-mass exoplanets

ABSTRACT The observed distribution of radii for exoplanets shows a bimodal form that can be explained by mass-loss from planetary atmospheres due to high-energy radiation emitted by their host stars. The location of the minimum of this radius distribution depends on the mass–radius relation, which i...

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Bibliographic Details
Published inMonthly notices of the Royal Astronomical Society Vol. 490; no. 1; pp. 15 - 20
Main Authors Owen, James E, Adams, Fred C
Format Journal Article
LanguageEnglish
Published 21.11.2019
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Summary:ABSTRACT The observed distribution of radii for exoplanets shows a bimodal form that can be explained by mass-loss from planetary atmospheres due to high-energy radiation emitted by their host stars. The location of the minimum of this radius distribution depends on the mass–radius relation, which in turn depends on the composition of planetary cores. Current studies suggest that super-Earth and mini-Neptune planets have iron-rich and hence largely Earth-like composition cores. This paper explores how non-zero planetary magnetic fields can decrease the expected mass-loss rates from these planets. These lower mass-loss rates, in turn, affect the location of the minimum of the radius distribution and the inferred chemical composition of the planetary cores.
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/stz2601