The Astronomical Journal (Jan 2024)
Atmospheric Metallicity and C/O of HD 189733 b from High-resolution Spectroscopy
- Luke Finnerty,
- Jerry W. Xuan,
- Yinzi Xin,
- Joshua Liberman,
- Tobias Schofield,
- Michael P. Fitzgerald,
- Shubh Agrawal,
- Ashley Baker,
- Randall Bartos,
- Geoffrey A. Blake,
- Benjamin Calvin,
- Sylvain Cetre,
- Jacques-Robert Delorme,
- Greg Doppmann,
- Daniel Echeverri,
- Chih-Chun Hsu,
- Nemanja Jovanovic,
- Ronald A. López,
- Emily C. Martin,
- Dimitri Mawet,
- Evan Morris,
- Jacklyn Pezzato,
- Jean-Baptiste Ruffio,
- Ben Sappey,
- Andrew Skemer,
- Taylor Venenciano,
- J. Kent Wallace,
- Nicole L. Wallack,
- Jason J. Wang,
- Ji Wang
Affiliations
- Luke Finnerty
- ORCiD
- Department of Physics & Astronomy, 430 Portola Plaza, University of California , Los Angeles, CA 90095, USA ; [email protected]
- Jerry W. Xuan
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Yinzi Xin
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Joshua Liberman
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA; James C. Wyant College of Optical Sciences, University of Arizona , Meinel Building 1630 E. University Boulevard, Tucson, AZ 85721, USA
- Tobias Schofield
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Michael P. Fitzgerald
- ORCiD
- Department of Physics & Astronomy, 430 Portola Plaza, University of California , Los Angeles, CA 90095, USA ; [email protected]
- Shubh Agrawal
- ORCiD
- Department of Physics and Astronomy, University of Pennsylvania , Philadelphia, PA 19104, USA
- Ashley Baker
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Randall Bartos
- Jet Propulsion Laboratory, California Institute of Technology , 4800 Oak Grove Drive, Pasadena, CA 91109, USA
- Geoffrey A. Blake
- ORCiD
- Division of Geological & Planetary Sciences, California Institute of Technology , Pasadena, CA 91125, USA
- Benjamin Calvin
- ORCiD
- Department of Physics & Astronomy, 430 Portola Plaza, University of California , Los Angeles, CA 90095, USA ; [email protected]; Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Sylvain Cetre
- W.M. Keck Observatory , 65-1120 Mamalahoa Hwy, Kamuela, HI 96743, USA
- Jacques-Robert Delorme
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA; W.M. Keck Observatory , 65-1120 Mamalahoa Hwy, Kamuela, HI 96743, USA
- Greg Doppmann
- W.M. Keck Observatory , 65-1120 Mamalahoa Hwy, Kamuela, HI 96743, USA
- Daniel Echeverri
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Chih-Chun Hsu
- ORCiD
- Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University , Evanston, IL 60208, USA
- Nemanja Jovanovic
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Ronald A. López
- ORCiD
- Department of Physics & Astronomy, 430 Portola Plaza, University of California , Los Angeles, CA 90095, USA ; [email protected]
- Emily C. Martin
- ORCiD
- Department of Astronomy & Astrophysics, University of California , Santa Cruz, CA 95064, USA
- Dimitri Mawet
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA; Jet Propulsion Laboratory, California Institute of Technology , 4800 Oak Grove Drive, Pasadena, CA 91109, USA
- Evan Morris
- Department of Astronomy & Astrophysics, University of California , Santa Cruz, CA 95064, USA
- Jacklyn Pezzato
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Jean-Baptiste Ruffio
- ORCiD
- Center for Astrophysics and Space Sciences, University of California , San Diego, La Jolla, CA 92093, USA
- Ben Sappey
- ORCiD
- Center for Astrophysics and Space Sciences, University of California , San Diego, La Jolla, CA 92093, USA
- Andrew Skemer
- ORCiD
- Department of Astronomy & Astrophysics, University of California , Santa Cruz, CA 95064, USA
- Taylor Venenciano
- ORCiD
- Physics and Astronomy Department, Pomona College , 333 N. College Way, Claremont, CA 91711, USA
- J. Kent Wallace
- ORCiD
- Jet Propulsion Laboratory, California Institute of Technology , 4800 Oak Grove Drive, Pasadena, CA 91109, USA
- Nicole L. Wallack
- ORCiD
- Earth and Planets Laboratory, Carnegie Institution for Science , Washington, DC 20015, USA
- Jason J. Wang
- ORCiD
- Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University , Evanston, IL 60208, USA
- Ji Wang
- ORCiD
- Department of Astronomy, The Ohio State University , 100 W 18th Avenue, Columbus, OH 43210 USA
- DOI
- https://doi.org/10.3847/1538-3881/ad1180
- Journal volume & issue
-
Vol. 167,
no. 1
p. 43
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 H _2 O, CO, CH _4 , NH _3 , HCN, and H _2 S, and the ^13 CO/ ^12 CO ratio. We measure mass fractions of ${\mathrm{logH}}_{2}{\rm{O}}=-{2.0}_{-0.4}^{+0.4}$ and $\mathrm{logCO}=-{2.2}_{-0.5}^{+0.5}$ , and place upper limits on the remaining species. Notably, we find logCH _4 < −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 (∼3 σ ) detection of ^13 CO, and the retrieved posteriors suggest a ^12 C/ ^13 C ratio similar to or substantially less than the local interstellar value. The possible ^13 C 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.
Keywords
- Hot Jupiters
- Exoplanets
- High resolution spectroscopy
- Exoplanet atmospheric composition
- Exoplanet atmospheres
