Vol. 577
In section 10. Planets and planetary systems

Spectrally resolved detection of sodium in the atmosphere of HD 189733b with the HARPS spectrograph

The authors obtained the first ever high-resolution spectrum of the sodium doublet in the hot Jupiter HD 189733b with the HARPS spectrograph. They analyzed the line shapes to provide constraints on the temperature in the low-pressure atmosphere. The temperatures increase from 1500 K in the lower atmosphere to about 3300 K 10,000 km above this layer. Measurements like this will enable a much better characterization of the upper atmospheres of these planets and will help understanding their mass-loss rates.