Tidal limits to planetary habitability

Rory Barnes, Brian Jackson, Richard J. Greenberg, Sean N. Raymond

Research output: Contribution to journalArticle

59 Citations (Scopus)

Abstract

The habitable zones (HZs) of main-sequence stars have traditionally been defined as the range of orbits that intercept the appropriate amount of stellar flux to permit surface water on a planet. Terrestrial exoplanets discovered to orbit M stars in these zones, which are close-in due to decreased stellar luminosity, may also undergo significant tidal heating. Tidal heating may span a wide range for terrestrial exoplanets and may significantly affect conditions near the surface. For example, if heating rates on an exoplanet are near or greater than that on Io (where tides drive volcanism that resurfaces the planet at least every 1 Myr) and produce similar surface conditions, then the development of life seems unlikely. On the other hand, if the tidal heating rate is less than the minimum to initiate plate tectonics, then CO2 may not be recycled through subduction, leading to a runaway greenhouse that sterilizes the planet. These two cases represent potential boundaries to habitability and are presented along with the range of the traditional HZ for main-sequence, low-mass stars. We propose a revised HZ that incorporates both stellar insolation and tidal heating. We apply these criteria to GJ 581 d and find that it is in the traditional HZ, but its tidal heating alone may be insufficient for plate tectonics.

Original languageEnglish (US)
JournalAstrophysical Journal
Volume700
Issue number1 PART 2
DOIs
StatePublished - 2009

Fingerprint

habitability
heating
extrasolar planets
planets
plates (tectonics)
planet
plate tectonics
stellar luminosity
orbits
insolation
M stars
Io
main sequence stars
greenhouses
tides
surface water
volcanism
tide
subduction
stars

Keywords

  • Astrobiology
  • Planetary systems
  • Stars: individual (GJ 581)
  • Stars: low-mass, brown dwarfs

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Tidal limits to planetary habitability. / Barnes, Rory; Jackson, Brian; Greenberg, Richard J.; Raymond, Sean N.

In: Astrophysical Journal, Vol. 700, No. 1 PART 2, 2009.

Research output: Contribution to journalArticle

Barnes, Rory ; Jackson, Brian ; Greenberg, Richard J. ; Raymond, Sean N. / Tidal limits to planetary habitability. In: Astrophysical Journal. 2009 ; Vol. 700, No. 1 PART 2.
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