The roles of tidal evolution and evaporative mass loss in the origin of CoRoT-7 b

Brian Jackson, Neil Miller, Rory Barnes, Sean N. Raymond, Jonathan J. Fortney, Richard Greenberg

Research output: Contribution to journalArticle

54 Scopus citations

Abstract

CoRoT-7 b is the first confirmed rocky exoplanet, but, with an orbital semimajor axis of 0.0172 au, its origins may be unlike any rocky planet in our Solar system. In this study, we consider the roles of tidal evolution and evaporative mass loss in CoRoT-7 b's history, which together have modified the planet's mass and orbit. If CoRoT-7 b has always been a rocky body, evaporation may have driven off almost half its original mass, but the mass loss may depend sensitively on the extent of tidal decay of its orbit. As tides caused CoRoT-7 b's orbit to decay, they brought the planet closer to its host star, thereby enhancing the mass loss rate. Such a large mass loss also suggests the possibility that CoRoT-7 b began as a gas giant planet and had its original atmosphere completely evaporated. In this case, we find that CoRoT-7 b's original mass probably did not exceed 200 Earth masses (about two-third of a Jupiter mass). Tides raised on the host star by the planet may have significantly reduced the orbital semimajor axis, perhaps causing the planet to migrate through mean-motion resonances with the other planet in the system, CoRoT-7 c. The coupling between tidal evolution and mass loss may be important not only for CoRoT-7 b but also for other close-in exoplanets, and future studies of mass loss and orbital evolution may provide insight into the origin and fate of close-in planets, both rocky and gaseous.

Original languageEnglish (US)
Pages (from-to)910-922
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume407
Issue number2
DOIs
StatePublished - Sep 1 2010

Keywords

  • Celestial mechanics
  • Planets and satellites: atmospheres
  • Planets and satellites: individual: CoRoT-7 b

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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