Three Possible Origins for the Gas Layer on Gj 1214b
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Seager_Three possible.pdf
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Author(s)
Rogers, Leslie Anne
Seager, Sara
Date Issued
May 2010
Journal
Astrophysical Journal
Publisher
IOP Publishing
Citation
Rogers, L. A., and S. Seager. “Three Possible Origins for the Gas Layer on Gj 1214b.” The Astrophysical Journal 716.2 (2010): 1208–1216. © 2010 IOP Publishing
Version
Final published version
Abstract
We present an analysis of the bulk composition of the MEarth transiting super-Earth exoplanet GJ 1214b using planet interior structure models. We consider three possible origins for the gas layer on GJ 1214b: direct accretion of gas from the protoplanetary nebula, sublimation of ices, and outgassing from rocky material. Armed only with measurements of the planet mass (M[subscript p] = 6.55 ± 0.98 M [subscript ⊕]), radius (R[subscript p] = 2.678 ± 0.13 R [subscript ⊕]), and stellar irradiation level, our main conclusion is that we cannot infer a unique composition. A diverse range of planet interiors fits the measured planet properties. Nonetheless, GJ 1214b's relatively low average density (ρ [subscript p] = 1870 ± 400 kg m[superscript –3][) means that it almost certainly has a significant gas component. Our second major conclusion is that under most conditions we consider GJ 1214b would not have liquid water. Even if the outer envelope is predominantly sublimated water ice, the envelope will likely consist of a super-fluid layer sandwiched between vapor above and plasma (electrically conductive fluid) below at greater depths. In our models, a low intrinsic planet luminosity (lsim2TW) is needed for a water envelope on GJ 1214b to pass through the liquid phase.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Massachusetts Institute of Technology. Department of Physics
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DOI of Published Version
https://doi.org/10.1088/0004-637x/716/2/1208
