Constraints on the exosphere of CoRoT-7b E. W. Guenther, J. Cabrera, A. Erikson, M. Fridlund, H. Lammer, A. Mura, H. Rauer, J. Schneider, M. Tulej, Ph. von Paris and P. Wurz A&A, 525 (2011) A24 Published online: 29 November 2010 DOI: 10.1051/0004-6361/201014868