Detection of water in the atmosphere of the hot Jupiter HD 102195b

The composition and structure of hot Jupiter atmospheres provide a fossil record of their primordial origins, potentially holding the key to distinguishing between the various proposed formation mechanisms. High-resolution spectroscopic observations of exoplanet atmospheres enable us to resolve molecular bands into many individual spectral lines in a pattern that is unique to each molecule. By then exploiting the Doppler shift of the planet over multiple nights we can separate the planet spectrum from that of the host star and Earths atmosphere. Here, we use the high-resolution infrared spectrograph IGRINS (R=45,000, λ=1.4-2.5 microns) on the 4.3m Discovery Channel Telescope to observe the spectrum of the hot Jupiter HD 102195b. Our analysis reveals a 4σ detection of water in the atmosphere of this heavily irradiated hot Jupiter.