Publications

PEPSI Investigation, Retrieval, and Atlas of Numerous Giant Atmospheres (PIRANGA). II.Phase-Resolved Cross-Correlation Transmission Spectroscopy of KELT-20b

ELT-20b is a well-studied exoplanet within the highly observable ultra hot Jupiter (UHJ) regime, yet its multidimensional atmospheric structure remains largely unconstrained. Recent advances in instrumentation and increased general circulation model (GCM) complexity have enabled observers to resolve the imprints of more intricate physical mechanisms in time-resolved data. We performed high-resolution cross-correlation transmission spectroscopy (HRCCTS) on a single transit time series of KELT-20b, observed with PEPSI on the LBT. We detect Fe I (11.9σ) and Fe II (23.7σ) and tentatively detect Na I (3.4σ) and Cr I (3.3σ) upon combining nineteen in-transit exposures.

Observability score of each neutral species considered in this study. Colored elements are more likely to be detected since their absorption lines are covered by the PEPSI bandpass ranges we use. Dark cells have fewer and/or shallower lines. Light gray cells were skipped because they don’t have significant lines in the PEPSI bandpass or did not have available opacities. Species with observability score of ∼ 0.2 or greater have been detected in at least one study, except for Ni I.

Read more: Lenhart et al. 2025, AJ, in press. eprint arXiv:2503.07719