ON THE ORBIT OF THE SHORT-PERIOD EXOPLANET WASP-19b
- Astrophysics Group, Keele University, Staffordshire, ST5 5BG (United Kingdom)
- SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, Fife, KY16 9SS (United Kingdom)
WASP-19b has the shortest orbital period of any known exoplanet, orbiting at only 1.2 times the Roche tidal radius. By observing the Rossiter-McLaughlin effect we show that WASP-19b's orbit is aligned, with {lambda} = 4.{sup 0}6 {+-} 5.{sup 0}2. Using, in addition, a spectroscopic vsin I and the observed rotation period we conclude that the obliquity, {psi}, is less than 20{sup 0}. Further, the eccentricity of the orbit is less than 0.02. We argue that hot Jupiters with orbital periods as short as that of WASP-19b are two orders of magnitude less common than hot Jupiters at the 3-4 day 'pileup'. We discuss the evolution of WASP-19b's orbit and argue that most likely it was first moved to near twice the Roche limit by third-body interactions, and has since spiralled inward to its current location under tidal decay. This is compatible with a stellar tidal-dissipation quality factor, Q'{sub *}, of order 10{sup 7}.
- OSTI ID:
- 21560416
- Journal Information:
- Astrophysical Journal Letters, Vol. 730, Issue 2; Other Information: DOI: 10.1088/2041-8205/730/2/L31; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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