Abstract
We report the discovery of WASP-6b, an inflated sub-Jupiter mass planet transiting every 3.3610060$^+ 0.0000022 $$_- 0.0000035 $ days a mildly metal-poor solar-type star of magnitude V = 11.9. A combined analysis of the WASP photometry, high-precision followup transit photometry and radial velocities yield a planetary mass M$_p$ = 0.503$^+0.019$$_-0.038$ M$_J$ and radius R$_p$ = 1.224$^+0.051$$_-0.052$ RJ, resulting in a density $$_p$ = 0.27 plusmn 0.05 $J. The mass and radius for the host star are Mast = 0.88$^+0.05$$_-0.08$ Msun and Rast = 0.870$^+0.025$$_-0.036$ Rsun. The non-zero orbital eccentricity e = 0.054+0.018$_-0.015$ that we measure suggests that the planet underwent a massive tidal heating 1 Gyr ago that could have contributed to its inflated radius. High-precision radial velocities obtained during a transit allow us to measure a sky-projected angle between the stellar spin and orbital axis $ = 11$^+14$$_-18$ deg. In addition to similar published measurements, this result favors a dominant migration mechanism based on tidal interactions with a protoplanetary disk. Based on data collected with the HARPS spectrograph at ESO La Silla Observatory in the programs 082.C-0040(E) and 082.C-0608. The photometric time-series and radial velocities (Tables 4, 5) used in this work are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/501/785
Original language | English |
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Pages (from-to) | 785-792 |
Number of pages | 8 |
Journal | Astronomy and Astrophysics |
Volume | 501 |
DOIs | |
Publication status | Published - 1 Jul 2009 |
Keywords
- binaries: eclipsing, stars: individual: WASP-6, planetary systems, techniques: photometric, techniques: radial velocities, techniques: spectroscopic