Search for signatures of atmospheres/exospheres in extra-solar planets

Kurzfassung

Information about the atmosphere of an extra-solar planet can be obtained by observing the light of the star through the planetary atmosphere during transit phases of the planet. This observation requirens an inclination of the planet's orbit close to 90°. If the inclination does not allow full transits, it may still be possible to detect signatures of the extended planetary exosphere. We have searched for absorption features in spectra og 51 Peg, Boo und HD209458 during transits of their planets through the lines of sight. Spectra in the optical wavelength range were taken using the UES spectrograph at the 4m William Herschel telescope at La Palma, Spain.