TY - JOUR
T1 - The effect of multiple heat sources on exomoon habitable zones
AU - Dobos, Vera
AU - Heller, René
AU - Turner, Edwin L.
N1 - Funding Information:
This research has been supported in part by the World Premier International Research Center Initiative, MEXT, Japan. V.D. has been supported by the Hungarian OTKA Grants K104607, K119993, and the Hungarian National Research, Development and Innovation Office (NKFIH) grant K-115709
Publisher Copyright:
© 2017 ESO.
PY - 2017/5/1
Y1 - 2017/5/1
N2 - With dozens of Jovian and super-Jovian exoplanets known to orbit their host stars in or near the stellar habitable zones, it has recently been suggested that moons the size of Mars could offer abundant surface habitats beyond the solar system. Several searches for such exomoons are now underway, and the exquisite astronomical data quality of upcoming space missions and ground-based extremely large telescopes could make the detection and characterization of exomoons possible in the near future. Here we explore the effects of tidal heating on the potential of Mars-to Earth-sized satellites to host liquid surface water, and we compare the tidal heating rates predicted by tidal equilibrium model and a viscoelastic model. In addition to tidal heating, we consider stellar radiation, planetary illumination and thermal heat from the planet. However, the effects of a possible moon atmosphere are neglected. We map the circumplanetary habitable zone for different stellar distances in specific star-planet-satellite configurations, and determine those regions where tidal heating dominates over stellar radiation. We find that the "thermostat effect" of the viscoelastic model is significant not just at large distances from the star, but also in the stellar habitable zone, where stellar radiation is prevalent. We also find that tidal heating of Mars-sized moons with eccentricities between 0.001 and 0.01 is the dominant energy source beyond 3-5 AU from a Sun-like star and beyond 0.4-0.6 AU from an M3 dwarf star. The latter would be easier to detect (if they exist), but their orbital stability might be under jeopardy due to the gravitational perturbations from the star.
AB - With dozens of Jovian and super-Jovian exoplanets known to orbit their host stars in or near the stellar habitable zones, it has recently been suggested that moons the size of Mars could offer abundant surface habitats beyond the solar system. Several searches for such exomoons are now underway, and the exquisite astronomical data quality of upcoming space missions and ground-based extremely large telescopes could make the detection and characterization of exomoons possible in the near future. Here we explore the effects of tidal heating on the potential of Mars-to Earth-sized satellites to host liquid surface water, and we compare the tidal heating rates predicted by tidal equilibrium model and a viscoelastic model. In addition to tidal heating, we consider stellar radiation, planetary illumination and thermal heat from the planet. However, the effects of a possible moon atmosphere are neglected. We map the circumplanetary habitable zone for different stellar distances in specific star-planet-satellite configurations, and determine those regions where tidal heating dominates over stellar radiation. We find that the "thermostat effect" of the viscoelastic model is significant not just at large distances from the star, but also in the stellar habitable zone, where stellar radiation is prevalent. We also find that tidal heating of Mars-sized moons with eccentricities between 0.001 and 0.01 is the dominant energy source beyond 3-5 AU from a Sun-like star and beyond 0.4-0.6 AU from an M3 dwarf star. The latter would be easier to detect (if they exist), but their orbital stability might be under jeopardy due to the gravitational perturbations from the star.
KW - Astrobiology
KW - Methods: Numerical
KW - Planets and satellites: General
KW - Planets and satellites: Interiors
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U2 - 10.1051/0004-6361/201730541
DO - 10.1051/0004-6361/201730541
M3 - Article
AN - SCOPUS:85018920507
SN - 0004-6361
VL - 601
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A91
ER -