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Title: Tidally distorted exoplanets: Density corrections for short-period hot-Jupiters based solely on observable parameters

The close proximity of short-period hot-Jupiters to their parent star means they are subject to extreme tidal forces. This has a profound effect on their structure and, as a result, density measurements that assume that the planet is spherical can be incorrect. We have simulated the tidally distorted surface for 34 known short-period hot-Jupiters, assuming surfaces of constant gravitational equipotential for the planet, and the resulting densities have been calculated based only on observed parameters of the exoplanet systems. Comparing these results to the density values, assuming the planets are spherical, shows that there is an appreciable change in the measured density for planets with very short periods (typically less than two days). For one of the shortest-period systems, WASP-19b, we determine a decrease in bulk density of 12% from the spherical case and, for the majority of systems in this study, this value is in the range of 1%-5%. On the other hand, we also find cases where the distortion is negligible (relative to the measurement errors on the planetary parameters) even in the cases of some very short period systems, depending on the mass ratio and planetary radius. For high-density gas planets requiring apparently anomalously large core masses,more » density corrections due to tidal deformation could become important for the shortest-period systems.« less
Authors:
; ; ;  [1] ; ;  [2] ;  [3]
  1. Astrophysics Research Centre, Queen's University Belfast, Belfast BT7 1NN (United Kingdom)
  2. Department of Physics and Astronomy, University of Warwick, Coventry CV4 7AL (United Kingdom)
  3. Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH (United Kingdom)
Publication Date:
OSTI Identifier:
22365691
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 789; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BULK DENSITY; CORRECTIONS; DEFORMATION; MASS; SATELLITE ATMOSPHERES; SIMULATION; SPHERICAL CONFIGURATION; STARS; SURFACES