EUV-driven mass-loss of protoplanetary cores with hydrogen-dominated atmospheres: the influences of ionization and orbital distance

We investigate the loss rates of the hydrogen atmospheres of terrestrial planets with a range of masses and orbital distances by assuming a stellar extreme ultraviolet (EUV) luminosity that is 100 times stronger than that of the current Sun. We apply a 1D upper atmosphere radiation absorption and hy...

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Bibliographic Details
Published in:Monthly notices of the Royal Astronomical Society 2016-08, Vol.460 (2), p.1300-1309
Main Authors: Erkaev, N. V., Lammer, H., Odert, P., Kislyakova, K. G., Johnstone, C. P., Güdel, M., Khodachenko, M. L.
Format: Article
Language:English
Subjects:
Comparative analysis
Fluid mechanics
Hydrogen
Hydrogen storage
Ionization
Luminosity
Mathematical models
Orbitals
Radiation
Radiation absorption
Star & galaxy formation
Stellar atmospheres
Ultraviolet
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Summary:We investigate the loss rates of the hydrogen atmospheres of terrestrial planets with a range of masses and orbital distances by assuming a stellar extreme ultraviolet (EUV) luminosity that is 100 times stronger than that of the current Sun. We apply a 1D upper atmosphere radiation absorption and hydrodynamic escape model that takes into account ionization, dissociation and recombination to calculate hydrogen mass-loss rates. We study the effects of the ionization, dissociation and recombination on the thermal mass-loss rates of hydrogen-dominated super-Earths and compare the results to those obtained by the energy-limited escape formula which is widely used for mass-loss evolution studies. Our results indicate that the energy-limited formula can to a great extent over- or underestimate the hydrogen mass-loss rates by amounts that depend on the stellar EUV flux and planetary parameters such as mass, size, effective temperature and EUV absorption radius.
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/stw935