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A spectral atlas of the atmosphere of WASP-189 b as seen in transmission with MAROON-X

Presentation #624.37 in the session Planetary Atmospheres - Hot Jupiters.

Published onApr 03, 2024
A spectral atlas of the atmosphere of WASP-189 b as seen in transmission with MAROON-X

Ultra-hot Jupiter-like exoplanets provide an ideal laboratory for testing the impact of stellar irradiation on the dynamics and chemical composition of their atmospheres. In this study, we observed two transits of the ultra-hot Jupiter WASP-189 b with MAROON-X/Gemini-North to probe the high-altitude atmospheric layers, using strong spectral absorption lines. Ca+ absorption is strong enough for analysis through time-resolved narrow-band spectroscopy, owing to its transition lines forming in those high-altitude layers. Calculating the stellar spectrum behind the planet at every orbital phase during the transit allows for the derivation of posterior distributions for the planetary and stellar parameters. This allows for the correction of the Rossiter-McLaughlin imprint on the transmission spectra. Using differential transmission spectroscopy, we detected strong absorption lines of Ca+, Ba+, Na, Hα, Mg, Fe and Fe+. The spectral absorption lines show no significant blue shifts that would indicate high-altitude winds, and further analysis is needed to investigate implications for atmospheric dynamics. These high signal-to-noise observations provide a benchmark data set for testing high-resolution retrievals and the limits of atmospheric models. We also simulate observations of WASP-189 b with ANDES/ELT, and show that ANDES will be highly sensitive to individual absorption lines of a myriad of elements and molecules, including TiO and CO.

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