New Frontiers of Exoplanet Science with High Resolution Cross Correlation Spectroscopy: Characterization of HD 209458b

High Resolution Cross Correlation Spectroscopy (HRCCS) is a novel method for ground-based characterization of exoplanets. It utilizes the planet’s motion through space around its host star to isolate the signals from hundreds to thousands of spectral lines from otherwise telluric and stellar dominated spectra. This higher spectral resolution also unlocks information and regions of the atmosphere otherwise inaccessible via low resolution spectroscopy. Additionally, high resolution spectra can be combined with low resolution data with minimal effort for a more complete view into the atmosphere than either method can provide individually.

The canonical hot-Jupiter HD 209458b has been the subject of numerous studies using HRCCS with VLT/CRIRES. However, these studies are not in agreement on the abundance or presence of H₂O, which was strongly detected by HST. In this study, we use IRTF/iSHELL to observe HD 209458b’s dayside thermal emission, examining the HRCCS capabilities of smaller telescopes as well as providing additional constraints on the abundances of CO, H₂O, and HCN in HD 209458b’s atmosphere. Our results hold implications for the capabilities of small, ground-based telescopes to characterize bright targets discovered by TESS and other surveys.