Spectroscopic study of the outer atmosphere of the exoplanet HD 189733 b

• Applicant: Dr. Stefan Czesla
• Subject Area: Astrophysics and Astronomy
• Term: from 2013 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 243354337

I propose to study the atmosphere of the hot Jovian planet HD 189733 b using high-resolution spectroscopy in the frame of a dissertation. The continuously increasing number of known extrasolar planetary systems reveals an enormous variety of planets with different masses, densities, orbital configurations and, therefore, most likely also highly dissimilar atmospheres. Jovian planets orbiting in close proximity to their host-stars - the hot Jupiters - are among the surprising discoveries.This application aims at the detection and analysis of the atmosphere of the hot Jovian planet HD 189733 b, which stands out from the roughly one thousand known exoplanets for its bright and active host star. The planned study is based on a set of ca. 250 high-resolution spectra, which I obtained on July 1st, 2013 using the UVES spectrograph. Furthermore, two data sets from the ESO- and KECK-archive are available, which have not yet been analyzed with respect to atmospheric absorption.After the data reduction, the planetary atmosphere shall be detected through the analysis of the Ca II H and K and H-alpha lines. Moreover, a flare covered by out data is to be analyzed, in particular with respect to atmospheric mass loss. Although a number of detections of HD 189733 b's atmosphere have been published already, the strength of the atmospheric absorption remains controversial.Because a major fraction of the relevant high-energy emission is potentially released during flares, a temporally variable atmosphere seems likely. Consequently, further measurements of atmospheric absorption are indispensable to better understand the atmosphere and mass loss of HD 189733 b.The extraordinarily high photometric stability of our data allows to include the color dependence of the transit in the analysis. This provides both a possibility to study the center-to-limb variation of the active host-star and another approach to study the planetary atmosphere in absorption.A continuously growing number of known planets ensues an increasing number of atmospheres to be studied.

• DFG Programme: Research Grants