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Full-Text Articles in Physical Sciences and Mathematics
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
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
Brian Jackson
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 …
Corot-7b: Super-Earth Or Super-Io?, Rory Barnes, Sean N. Raymond, Richard Greenberg, Brian Jackson, Nathan A. Kaib
Corot-7b: Super-Earth Or Super-Io?, Rory Barnes, Sean N. Raymond, Richard Greenberg, Brian Jackson, Nathan A. Kaib
Brian Jackson
CoRoT-7b, a planet about 70% larger than the Earth orbiting a Sun-like star, is the first-discovered rocky exoplanet, and hence has been dubbed a "super-Earth." Some initial studies suggested that since the planet is so close to its host star, it receives enough insolation to partially melt its surface. However, these past studies failed to take into consideration the role that tides may play in this system. Even if the planet's eccentricity has always been zero, we show that tidal decay of the semimajor axis could have been large enough that the planet formed on a wider orbit which received …
Tidal Heating Of Terrestrial Extrasolar Planets And Implications For Their Habitability, Brian Jackson, Rory Barnes, Richard Greenberg
Tidal Heating Of Terrestrial Extrasolar Planets And Implications For Their Habitability, Brian Jackson, Rory Barnes, Richard Greenberg
Brian Jackson
The tidal heating of hypothetical rocky (or terrestrial) extrasolar planets spans a wide range of values depending on stellar masses and initial orbits. Tidal heating may be sufficiently large (in many cases, in excess of radiogenic heating) and long-lived to drive plate tectonics, similar to the Earth's, which may enhance the planet's habitability. In other cases, excessive tidal heating may result in Io-like planets with violent volcanism, probably rendering them unsuitable for life. On water-rich planets, tidal heating may generate subsurface oceans analogous to Europa's with similar prospects for habitability. Tidal heating may enhance the outgassing of volatiles, contributing to …
Tidal Heating Of Extrasolar Planets, Brian Jackson, Richard Greenberg, Rory Barnes
Tidal Heating Of Extrasolar Planets, Brian Jackson, Richard Greenberg, Rory Barnes
Brian Jackson
Extrasolar planets close to their host stars have likely undergone significant tidal evolution since the time of their formation. Tides probably dominated their orbital evolution once the dust and gas cleared away, and as the orbits evolved there was substantial tidal heating within the planets. The tidal heating history of each planet may have contributed significantly to the thermal budget governing the planet's physical properties, including its radius, which in many cases may be measured by observing transit events. Typically, tidal heating increases as a planet moves inward toward its star and then decreases as its orbit circularizes. Here we …
Tidal Evolution Of Close-In Extrasolar Planets, Brian Jackson, Richard Greenberg, Rory Barnes
Tidal Evolution Of Close-In Extrasolar Planets, Brian Jackson, Richard Greenberg, Rory Barnes
Brian Jackson
The distribution of eccentricities e of extrasolar planets with semimajor axes a > 0.2 AU is very uniform, and values for e are relatively large, averaging 0.3 and broadly distributed up to near 1. For a < 0.2 AU, eccentricities are much smaller (most e < 0.2), a characteristic widely attributed to damping by tides after the planets formed and the protoplanetary gas disk dissipated. Most previous estimates of the tidal damping considered the tides raised on the planets, but ignored the tides raised on the stars. Most also assumed specific values for the planets' poorly constrained tidal dissipation parameter Qp. Perhaps most important, in many studies the strongly coupled evolution between e and a was ignored. We have now integrated the coupled tidal evolution equations for e and a over the estimated age of each planet, and confirmed that the distribution of initial e values of close-in planets matches that of the general population for reasonable Q values, with the best fits for stellar and planetary Q being ~105.5 and ~106.5, respectively. The accompanying evolution of a values shows most close-in planets had significantly larger a at the start of tidal migration. The earlier gas disk migration did not bring all planets to their current orbits. The current small values of a were only reached gradually due to tides over the lifetimes of the planets. These results may have important implications for planet formation models, atmospheric models of "hot Jupiters," and the success of transit surveys.