TY - JOUR
T1 - On the Orbit of the Short-period Exoplanet WASP-19b
AU - Hellier, C.
AU - Anderson, D.~R.
AU - Collier-Cameron, A.
AU - Miller, G.~R.~M.
AU - Queloz, D.
AU - Smalley, B.
AU - Southworth, J.
AU - Triaud, A.~H.~M.~J.
PY - 2011/4/1
Y1 - 2011/4/1
N2 - 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 $ = 4fdg6 plusmn 5fdg2. Using, in addition, a spectroscopic vsin I and the observed rotation period we conclude that the obliquity, $, is less than 20deg. Further, the eccentricity of the orbit is less than 0.02. We argue that hot Jupiters with orbital periods as short as that of WASP-19b are two orders of magnitude less common than hot Jupiters at the 3-4 day ``pileup.'' We discuss the evolution of WASP-19b's orbit and argue that most likely it was first moved to near twice the Roche limit by third-body interactions, and has since spiralled inward to its current location under tidal decay. This is compatible with a stellar tidal-dissipation quality factor, Q'$_*$, of order 10$^7$.
AB - 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 $ = 4fdg6 plusmn 5fdg2. Using, in addition, a spectroscopic vsin I and the observed rotation period we conclude that the obliquity, $, is less than 20deg. Further, the eccentricity of the orbit is less than 0.02. We argue that hot Jupiters with orbital periods as short as that of WASP-19b are two orders of magnitude less common than hot Jupiters at the 3-4 day ``pileup.'' We discuss the evolution of WASP-19b's orbit and argue that most likely it was first moved to near twice the Roche limit by third-body interactions, and has since spiralled inward to its current location under tidal decay. This is compatible with a stellar tidal-dissipation quality factor, Q'$_*$, of order 10$^7$.
KW - planetary systems, stars: individual: WASP-19
U2 - 10.1088/2041-8205/730/2/L31
DO - 10.1088/2041-8205/730/2/L31
M3 - Article
SN - 2041-8205
VL - 730
SP - L31
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
ER -