A cometary origin for CO in the stratosphere of Saturn? T. Cavalié, P. Hartogh, F. Billebaud, M. Dobrijevic, T. Fouchet, E. Lellouch, T. Encrenaz, J. Brillet and G. H. Moriarty-Schieven A&A, 510 (2010) A88 Published online: 17 February 2010 DOI: 10.1051/0004-6361/200912909