He I λ10 830 transmission spectroscopy: A new window on the dynamics of planetary atmospheres

• Applicant: Dr. Stefan Czesla
• Subject Area: Astrophysics and Astronomy
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 446251633

Planetary atmosphere have become a focus of astronomical research. Transmission spectroscopy is a powerful tool to study them. Of particular interest in this context are the He I 10830 triplet lines, because they allow to study the outer planetary atmosphere, including planetary winds, from the ground. Therefore, I propose a comprehensive observational and theoretical study of He I 10830 transmission spectra. To date, about a half a dozen system with He I 10830 line transmission signals are known. Their strengths appears to correlate with the activity level of the host star. Many observations of the He I 10830 lines already enable us to study line profiles and shifts, allowing us more detailed analysis of the dynamics of the planetary atmosphere. We played a leading role in this effort, and I intend to study more systems observationally. However, more observations will not resolve all problems in the interpretation of the signals. In particular, effects caused by the atmosphere of the Earth and that of the star, which is transited, can adversely affect the transmission spectra. Therefore, I will thoroughly examine these effects to assess their impact on the interpretation of the He I 10830 signals. My project allows me to combine experience in several fields. It is fully consistent with the SPP funding guidelines and benefits from being incorporated into its scientific community.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1992: Exploring the diversity of extrasolar planets