Atmospheric signatures by transit of HD209458 with VLT/UVES

Abstract

In our search for clues as to the nature of the exosphere of HD209458 (Moutou et al., 2001 ; Moutou et al., 2003, Iro et al., 2004), we have acquired VLT/UVES data during an ambitious observational campaign performed in June-September 2002 and covering 6 transits of the exoplanet. The resolving power was R=100000 in the 0.475-0.68 micron range. We search for ions and neutral molecules (such as H2O+, CO+, CH+, etc) originating in the planets exosphere and located in the evaporated material around the planet, occulting its primary star. We present in this paper a tentative search in the spectral regions where features of sodium or H2O+ can be present. © 2006 International Astronomical Union.