Clearing the Path to Biosignatures: Mitigating Stellar Contamination with TACHELES and MOSHE

The field of exoplanet atmospheric characterization through transmission spectroscopy has seen significant recent advancements. Historically reliant on ground-based facilities and the Hubble Space Telescope (HST), the technique has been revolutionized by the James Webb Space Telescope (JWST), enabling the discovery of new molecular species and the precise determination of exoplanetary atmospheric properties. Despite JWST's capabilities, a critical limitation in transmission spectroscopy has emerged: host star variability. Unaccounted stellar activity introduces noise that can mimic or mask atmospheric signals, posing a major obstacle to the unequivocal detection of faint molecular features, particularly biosignatures in the atmospheres of Earth-like exoplanets. Given that a substantial portion of JWST observing time is dedicated to this pursuit, mitigating this effect is essential for scientific progress. This presentation introduces two recently developed methodologies designed to rigorously address the impact of stellar contamination: Transits Across CHromosphEricaLly activE Stars (TACHELES) and Multi-epOch Spectroscopy of Habitable Exoplanets (MOSHE). An overview of the foundational principles and the first observational results from both techniques will be presented. The discussion will conclude with a forward-looking perspective on how these methods will shape the near-future strategy for exoplanet atmospheric surveys.

Note:
Volker is a candidate for a faculty position in the department.

Anyone interested in meeting with him, please pencil yourself in here:

https://docs.google.com/spreadsheets/d/14ySMR2SC6gS-ohOjT-fDUbDRNuDc9Jb…