Search For Exospheric Signatures From Transiting Planets

Abstract

We searched for spectral signatures from the exosphere of HD209458 in the UV and the near-IR with UVES and ISAAC at the VLT. We looked in particular for the helium absorption feature at 10 830 à predicted to be among the strongest ones. The upper limit of the He I line derived is 0.5% at 3 $σ$ for a 3 à bandwith. Planet-induced chromospheric activity search on HD209458 was also performed.

2 pages, LaTeX with 1 EPS figure embedded, using newpasp.sty (supplied). To appear in the proceedings of the XIXth IAP colloquium "Extrasolar Planets: Today and Tomorrow" held in Paris, France, 2003 June 30 -- July 4, ASP Conf. Ser