Spectrally resolved detection of sodium in the atmosphere of HD 189733b with the HARPS spectrograph A. Wyttenbach, D. Ehrenreich, C. Lovis, S. Udry and F. Pepe A&A, 577 (2015) A62 Published online: 05 May 2015 DOI: 10.1051/0004-6361/201525729