학술논문
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
Document Type
article
Author
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; Christian Veillet; Fei Yan
Source
The Astronomical Journal, Vol 165, Iss 4, p 157 (2023)
Subject
Language
English
ISSN
1538-3881
Abstract
Recent observations have shown that the atmospheres of ultrahot 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 a previous detection of Fe i in emission at 16.9 σ . Our search for the inversion agents TiO, VO, FeH, and CaH results in non-detections. Using injection-recovery testing we set 4 σ upper limits upon the volume mixing ratios for these constituents as low as ∼1 × 10 ^−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.