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Title: PLANETS ON THE EDGE

Hot Jupiters formed through circularization of high-eccentricity orbits should be found at orbital separations a exceeding twice that of their Roche limit a {sub R}. Nevertheless, about a dozen giant planets have now been found well within this limit (a {sub R} < a < 2 a {sub R}), with one coming as close as 1.2 a {sub R}. In this Letter, we show that orbital decay (starting beyond 2 a {sub R}) driven by tidal dissipation in the star can naturally explain these objects. For a few systems (WASP-4 and 19), this explanation requires the linear reduction in convective tidal dissipation proposed originally by Zahn and verified by recent numerical simulations, but rules out the quadratic prescription proposed by Goldreich and Nicholson. Additionally, we find that WASP-19-like systems could potentially provide direct empirical constraints on tidal dissipation, as we could soon be able to measure their orbital decay through high precision transit timing measurements.
Authors:
;  [1]
  1. Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3112 (United States)
Publication Date:
OSTI Identifier:
22365839
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 787; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCURACY; COMPUTERIZED SIMULATION; JUPITER PLANET; LIMITING VALUES; ORBITS; POTENTIALS; SATELLITES; STAR EVOLUTION; STARS