The Astronomical Journal (Jan 2025)
HD 206893 B at High Spectral Resolution with the Keck Planet Imager and Characterizer
- Ben Sappey,
- Quinn Konopacky,
- Clarissa R. Do Ó,
- Travis Barman,
- Jean-Baptiste Ruffio,
- Jason Wang,
- Christopher A. Theissen,
- Luke Finnerty,
- Jerry Xuan,
- Katelyn Hortsman,
- Dimitri Mawet,
- Yapeng Zhang,
- Julie Inglis,
- Nicole L. Wallack,
- Aniket Sanghi,
- Ashley Baker,
- Randall Bartos,
- Geoffrey A. Blake,
- Charlotte Z. Bond,
- Benjamin Calvin,
- Sylvain Cetre,
- Jacques-Robert Delorme,
- Greg Doppmann,
- Daniel Echeverri,
- Michael P. Fitzgerald,
- Chih-Chun Hsu,
- Nemanja Jovanovic,
- Joshua Liberman,
- Ronald A. López,
- Emily C. Martin,
- Evan Morris,
- Jacklyn Pezzato-Rovner,
- Caprice L. Phillips,
- Garreth Ruane,
- Tobias Schofield,
- Andrew Skemer,
- Taylor Venenciano,
- J. Kent Wallace,
- Ji Wang,
- Peter Wizinowich,
- Yinzi Xin
Affiliations
- Ben Sappey
- ORCiD
- Department of Physics, University of California , San Diego, La Jolla, CA 92093, USA
- Quinn Konopacky
- ORCiD
- Department of Astronomy and Astrophysics, University of California , San Diego, La Jolla, CA 92093, USA
- Clarissa R. Do Ó
- ORCiD
- Department of Physics, University of California , San Diego, La Jolla, CA 92093, USA
- Travis Barman
- ORCiD
- Lunar and Planetary Laboratory, University of Arizona , Tucson, AZ 85721, USA
- Jean-Baptiste Ruffio
- ORCiD
- Department of Astronomy and Astrophysics, University of California , San Diego, La Jolla, CA 92093, USA
- Jason Wang
- ORCiD
- Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University , Evanston, IL 60208, USA
- Christopher A. Theissen
- ORCiD
- Department of Astronomy and Astrophysics, University of California , San Diego, La Jolla, CA 92093, USA
- Luke Finnerty
- ORCiD
- Department of Physics & Astronomy, 430 Portola Plaza, University of California , Los Angeles, CA 90095, USA
- Jerry Xuan
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Katelyn Hortsman
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, 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
- Yapeng Zhang
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Julie Inglis
- ORCiD
- Division of Geological & Planetary Sciences, California Institute of Technology , Pasadena, CA 91125, USA
- Nicole L. Wallack
- ORCiD
- Earth and Planets Laboratory, Carnegie Institution for Science , Washington, DC 20015, USA
- Aniket Sanghi
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, 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
- Charlotte Z. Bond
- UK Astronomy Technology Centre, Royal Observatory , Edinburgh EH9 3HJ, UK
- Benjamin Calvin
- ORCiD
- Department of Physics & Astronomy, 430 Portola Plaza, University of California , Los Angeles, CA 90095, USA; Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Sylvain Cetre
- W. M. Keck Observatory , 65-1120 Mamalahoa Hwy, Kamuela, HI, USA
- Jacques-Robert Delorme
- ORCiD
- W. M. Keck Observatory , 65-1120 Mamalahoa Hwy, Kamuela, HI, USA
- Greg Doppmann
- W. M. Keck Observatory , 65-1120 Mamalahoa Hwy, Kamuela, HI, USA
- Daniel Echeverri
- ORCiD
- 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
- 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
- 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
- Ronald A. López
- ORCiD
- Department of Physics & Astronomy, 430 Portola Plaza, University of California , Los Angeles, CA 90095, USA
- Emily C. Martin
- ORCiD
- Department of Astronomy & Astrophysics, University of California , Santa Cruz, CA 95064, USA
- Evan Morris
- Department of Astronomy & Astrophysics, University of California , Santa Cruz, CA 95064, USA
- Jacklyn Pezzato-Rovner
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Caprice L. Phillips
- ORCiD
- Department of Astronomy, The Ohio State University , 100 W 18th Avenue, Columbus, OH 43210, USA
- Garreth Ruane
- ORCiD
- Jet Propulsion Laboratory, California Institute of Technology , 4800 Oak Grove Drive, Pasadena, CA 91109, USA
- Tobias Schofield
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Andrew Skemer
- Department of Astronomy & Astrophysics, University of California , Santa Cruz, CA 95064, USA
- Taylor Venenciano
- 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
- Ji Wang
- ORCiD
- Department of Astronomy, The Ohio State University , 100 W 18th Avenue, Columbus, OH 43210, USA
- Peter Wizinowich
- W. M. Keck Observatory , 65-1120 Mamalahoa Hwy, Kamuela, HI, USA
- Yinzi Xin
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- DOI
- https://doi.org/10.3847/1538-3881/adad70
- Journal volume & issue
-
Vol. 169,
no. 3
p. 175
Abstract
We present an atmospheric characterization and orbital analysis of HD 206893 B, an exceptionally red, L/T-transition substellar companion in a multiplanetary system, via Keck Planet Imager and Characterizer (KPIC) high-resolution ( R ∼ 35,000) K- band spectroscopy. Using PHOENIX atmospheric models in a forward-model framework that fits the spectrum of the companion and diffracted starlight simultaneously, we detect HD 206893 B at >8 σ significance via cross correlation in two epochs. We find an effective temperature for the companion of 1634 ${}_{-38}^{+72}$ K and a $\mathrm{log}\,g$ of 4.55 ${}_{-0.22}^{+0.17}$ . Only accounting for statistical uncertainties, we measure the carbon-oxygen ratio (C/O) of this companion to be 0.57 ± 0.02, or near-solar while assuming solar metallicity. The C/O ratio we measure fits the tentative trend of >4 M _Jup companions having near-solar C/O ratios while less massive companions have greater-than-solar C/O ratios. Using substellar evolution models, we find an age of 112 ${}_{-22}^{+36}$ Myr, a mass of 22.7 ${}_{-1.7}^{+2.5}$ M _Jup , and a radius of 1.11 ± 0.03 R _Jup for this companion. We also use KPIC radial velocity data to fit the orbit of HD 206893 B and analyze the orbital stability of this system. We find that the orbital stability is relatively independent of the mass of HD 206893 B, and favors an orbital configuration where B and its interior planetary companion, HD 206893 c, are coplanar. The measured C/O ratio coupled with the current architecture of the system cannot rule out the core accretion scenario, nor the disk fragmentation scenario regarding the formation pathway of HD 206893 B.
Keywords
- Exoplanet formation
- Exoplanet atmospheric composition
- Exoplanet atmospheric dynamics
- High resolution spectroscopy
- High contrast spectroscopy
