The PEPSI Exoplanet Transit Survey (PETS). II. A Deep Search for Thermal Inversion Agents in KELT-20 b/MASCARA-2 b with Emission and Transmission Spectroscopy

分类： 天文学 >> 天文学 提交时间： 2023-02-19

Marshall C. Johnson Ji Wang Anusha Pai Asnodkar Aldo S. Bonomo B. Scott Gaudi Thomas Henning Ilya Ilyin Engin Keles Luca Malavolta Matthias Mallonn Karan Molaverdikhani Valerio Nascimbeni Jennifer Patience Katja Poppenhaeger Gaetano Scandariato Everett Schlawin Evgenya Shkolnik Daniela Sicilia Alessandro Sozzetti Klaus G. Strassmeier

摘要： Recent observations have shown that the atmospheres of ultra hot Jupiters (UHJs) commonly possess temperature inversions, where the temperature increases with increasing altitude. Nonetheless, which opacity sources are responsible for the presence of these inversions remains largely observationally unconstrained. We used LBT/PEPSI to observe the atmosphere of the UHJ KELT-20 b in both transmission and emission in order to search for molecular agents which could be responsible for the temperature inversion. We validate our methodology by confirming previous detections of Fe I in emission at $16.9\sigma$. Our search for the inversion agents TiO, VO, FeH, and CaH results in non-detections. Using injection-recovery testing we set $4\sigma$ upper limits upon the volume mixing ratios for these constituents as low as $\sim1\times10^{-9}$ for TiO. For TiO, VO, and CaH, our limits are much lower than expectations from an equilibrium chemical model, while we cannot set constraining limits on FeH with our data. We thus rule out TiO and CaH as the source of the temperature inversion in KELT-20 b, and VO only if the line lists are sufficiently accurate.

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