Volume 534, October 2011
|Number of page(s)||8|
|Section||Planets and planetary systems|
|Published online||22 September 2011|
Astrophysics Group, Keele University, Staffordshire ST5 5BG, UK
2 SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, Fife KY16 9SS, UK
3 Institut d’Astrophysique et de Géophysique, Université de Liège, 17 Allée du 6 Août, Bât. B5C, Liège 1, Belgium
4 Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290 Sauverny, Switzerland
5 Oversky, 47 Allée des Palanques, 33127 Saint Jean d’Illac, France
Received: 30 June 2011
Accepted: 1 September 2011
We report on spectroscopic and photometric observations through transits of the exoplanets WASP-22b and WASP-26b, intended to determine the systems’ spin-orbit angles. We combine these data with existing data to refine the system parameters. We measure a sky-projected spin-orbit angle of 22 ± 16° for WASP-22b, showing the planet’s orbit to be prograde and, perhaps, slightly misaligned. We do not detect the Rossiter-McLaughlin effect of WASP-26b due to its low amplitude and observation noise. We place 3-σ upper limits on orbital eccentricity of 0.063 for WASP-22b and 0.050 for WASP-26b. After refining the drift in the systemic velocity of WASP-22 found by Maxted et al. (2010, AJ, 140, 2007), we find the third body in the system to have a minimum-mass of 5.3 ± 0.3 MJup (a3 / 5 AU)2, where a3 is the orbital distance of the third body.
Key words: binaries: eclipsing / planetary systems / stars: individual: WASP-22 / stars: individual: WASP-26
Based on observations made with the HARPS spectrograph on the 3.6-m ESO telescope (proposal 085.C-0393), the 0.6-m Belgian TRAPPIST telescope, and the CORALIE spectrograph and the Euler camera on the 1.2-m Euler Swiss telescope, all at the ESO La Silla Observatory, Chile.
The photometric time-series and radial velocity data used in this work are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (184.108.40.206) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/534/A16
© ESO, 2011
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