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 deg 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-sigma 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.
@article{arxiv.1106.6092,
title = {Spin-orbit measurements and refined parameters for the exoplanet systems WASP-22 and WASP-26},
author = {D. R. Anderson and A. Collier Cameron and M. Gillon and C. Hellier and E. Jehin and M. Lendl and D. Queloz and B. Smalley and A. H. M. J. Triaud and M. Vanhuysse},
journal= {arXiv preprint arXiv:1106.6092},
year = {2015}
}
Comments
As accepted for publication in A&A. 8 pages, 4 figures, 3 tables. (fixed typo in abstract)