WASP-21b: a hot-Saturn exoplanet transiting a thick disc star F. Bouchy, L. Hebb, I. Skillen, A. Collier Cameron, B. Smalley, S. Udry, D. R. Anderson, I. Boisse, B. Enoch, C. A. Haswell et al. (18 more) A&A, 519 (2010) A98 Published online: 17 September 2010 DOI: 10.1051/0004-6361/201014817