Atmospheric Metallicity and C/O of HD 189733 b from High-resolution Spectroscopy
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Finnerty, L.Xuan, J.W.
Xin, Y.
Liberman, J.
Schofield, T.
Fitzgerald, M.P.
Agrawal, S.
Baker, A.
Bartos, R.
Blake, G.A.
Calvin, B.
Cetre, S.
Delorme, J.-R.
Doppmann, G.
Echeverri, D.
Hsu, C.-C.
Jovanovic, N.
López, R.A.
Martin, E.C.
Mawet, D.
Morris, E.
Pezzato, J.
Ruffio, J.-B.
Sappey, B.
Skemer, A.
Venenciano, T.
Wallace, J.K.
Wallack, N.L.
Wang, J.J.
Wang, J.
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James C. Wyant College of Optical Sciences, University of ArizonaIssue Date
2024-01-02
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American Astronomical SocietyCitation
Luke Finnerty et al 2024 AJ 167 43Journal
Astronomical JournalRights
© 2024. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
We present high-resolution K-band emission spectra of the quintessential hot Jupiter HD 189733 b from the Keck Planet Imager and Characterizer. Using a Bayesian retrieval framework, we fit the dayside pressure-temperature profile, orbital kinematics, mass-mixing ratios of H2O, CO, CH4, NH3, HCN, and H2S, and the 13CO/12CO ratio. We measure mass fractions of logH 2 O = − 2.0 − 0.4 + 0.4 and logCO = − 2.2 − 0.5 + 0.5 , and place upper limits on the remaining species. Notably, we find logCH4 < −4.5 at 99% confidence, despite its anticipated presence at the equilibrium temperature of HD 189733 b assuming local thermal equilibrium. We make a tentative (∼3σ) detection of 13CO, and the retrieved posteriors suggest a 12C/13C ratio similar to or substantially less than the local interstellar value. The possible 13C enrichment would be consistent with accretion of fractionated material in ices or in the protoplanetary disk midplane. The retrieved abundances correspond to a substantially substellar atmospheric C/O = 0.3 ± 0.1, while the carbon and oxygen abundances are stellar to slightly superstellar, consistent with core-accretion models which predict an inverse correlation between C/O and metallicity. The specific combination of low C/O and high metallicity suggests significant accretion of solid material may have occurred late in the formation process of HD 189733 b. © 2024. The Author(s). Published by the American Astronomical Society.Note
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0004-6256Version
Final Published Versionae974a485f413a2113503eed53cd6c53
10.3847/1538-3881/ad1180
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Except where otherwise noted, this item's license is described as © 2024. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence.