Combined High and Low Resolution Atmospheric Retrieval on a Canonical Hot Jupiter

We present High Resolution Cross Correlation Spectroscopy (HRCCS) observations and atmospheric retrieval results of a canonical Hot Jupiter, HD 209458b. HRCCS is a novel technique used to characterize exoplanets with ground-based instruments by utilizing the planet’s time-resolved Doppler shifted signal to separate it from the dominant stellar and telluric lines. The high spectral resolution along with wide wavelength coverage allows for robust constraints on molecular abundances and thermal structures using Bayesian retrieval techniques. In addition, high resolution data can be combined with low resolution space-based data into one retrieval framework, allowing for a wide range of altitudes to be probed and integrating continuum information otherwise lost during detrending procedures in HRCCS.

We present our results using data taken from the IGRINS instrument (R ~ 45000) at Gemini South combined with published low resolution data taken using WFC3 on HST (R ~ 70) and the IRAC instrument on the Spitzer Space Telescope. These high fidelity data sets combined with a wide range of probed pressures, provide robust constraints on the abundances of H20 and CO as well as the thermal structure of the atmosphere of HD209458b.