The Astronomical Journal (Jan 2024)
Atmospheric Characterization of the Super-Jupiter HIP 99770 b with KPIC
- Yapeng Zhang,
- Jerry W. Xuan,
- Dimitri Mawet,
- Jason J. Wang,
- Chih-Chun Hsu,
- Jean-Bapiste Ruffio,
- Heather A. Knutson,
- Julie Inglis,
- Geoffrey A. Blake,
- Yayaati Chachan,
- Katelyn Horstman,
- Ashley Baker,
- Randall Bartos,
- Benjamin Calvin,
- Sylvain Cetre,
- Jacques-Robert Delorme,
- Greg Doppmann,
- Daniel Echeverri,
- Luke Finnerty,
- Michael P. Fitzgerald,
- Nemanja Jovanovic,
- Joshua Liberman,
- Ronald A. López,
- Evan Morris,
- Jacklyn Pezzato,
- Ben Sappey,
- Tobias Schofield,
- Andrew Skemer,
- J. Kent Wallace,
- Ji Wang,
- Clarissa R. Do Ó
Affiliations
- Yapeng Zhang
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Jerry W. Xuan
- ORCiD
- 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
- 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
- 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
- Jean-Bapiste Ruffio
- ORCiD
- Department of Astronomy & Astrophysics, University of California , San Diego, La Jolla, CA 92093, USA
- Heather A. Knutson
- ORCiD
- Division of Geological & Planetary Sciences, California Institute of Technology , Pasadena, CA 91125, USA
- Julie Inglis
- ORCiD
- Division of Geological & Planetary Sciences, California Institute of Technology , Pasadena, CA 91125, USA
- Geoffrey A. Blake
- ORCiD
- Division of Geological & Planetary Sciences, California Institute of Technology , Pasadena, CA 91125, USA
- Yayaati Chachan
- ORCiD
- Department of Physics and Trottier Space Institute, McGill University , 3600 rue University, Montreal, QC H3A 2T8, Canada; Trottier Institute for Research on Exoplanets (iREx), Université de Montréal , Canada
- Katelyn Horstman
- 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 Dr., Pasadena, CA 91109, USA
- Benjamin Calvin
- ORCiD
- Department of Physics & Astronomy, 430 Portola Plaza, University of California , Los Angeles, CA 90095, 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
- Luke Finnerty
- ORCiD
- Department of Physics & Astronomy, 430 Portola Plaza, University of California , Los Angeles, CA 90095, USA
- Michael P. Fitzgerald
- ORCiD
- Department of Physics & Astronomy, 430 Portola Plaza, University of California , Los Angeles, CA 90095, 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 Blvd., Tucson, AZ 85721, USA
- Ronald A. López
- ORCiD
- Department of Physics & Astronomy, 430 Portola Plaza, University of California , Los Angeles, CA 90095, USA
- Evan Morris
- ORCiD
- Department of Astronomy & Astrophysics, University of California, Santa Cruz , Santa Cruz, CA95064, USA
- Jacklyn Pezzato
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Ben Sappey
- ORCiD
- Department of Astronomy & Astrophysics, University of California , San Diego, La Jolla, CA 92093, USA
- Tobias Schofield
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Andrew Skemer
- ORCiD
- Department of Astronomy & Astrophysics, University of California, Santa Cruz , Santa Cruz, CA95064, USA
- J. Kent Wallace
- ORCiD
- Jet Propulsion Laboratory, California Institute of Technology , 4800 Oak Grove Dr., Pasadena, CA 91109, USA
- Ji Wang
- ORCiD
- Department of Astronomy, The Ohio State University , 100 W. 18th Ave., Columbus, OH 43210 USA
- Clarissa R. Do Ó
- ORCiD
- Department of Physics, University of California , San Diego, La Jolla, CA 92093, USA
- DOI
- https://doi.org/10.3847/1538-3881/ad6609
- Journal volume & issue
-
Vol. 168,
no. 3
p. 131
Abstract
Young, self-luminous super-Jovian companions discovered by direct imaging provide a challenging test for planet formation and evolution theories. By spectroscopically characterizing the atmospheric compositions of these super-Jupiters, we can constrain their formation histories. Here we present studies of the recently discovered HIP 99770 b, a 16 M _Jup high-contrast companion on a 17 au orbit, using the fiber-fed high-resolution spectrograph KPIC ( ${ \mathcal R }$ ∼ 35,000) on the Keck II telescope. Our K -band observations led to detections of H _2 O and CO in the atmosphere of HIP 99770 b. We carried out free retrieval analyses using petitRADTRANS to measure its chemical abundances, including the metallicity and C/O ratio, projected rotation velocity ( $v\sin i$ ), and radial velocity (RV). We found that the companion’s atmosphere has C/O $=\,{0.55}_{-0.04}^{+0.06}$ and [M/H] $=\,{0.26}_{-0.23}^{+0.24}$ (1 σ confidence intervals), values consistent with those of the Sun and with a companion formation via gravitational instability or core accretion. The projected rotation velocity $v\sin (i)\lt 7.8$ km s ^−1 is small relative to other directly imaged companions with similar masses and ages. This may imply a nearly pole-on orientation or effective magnetic braking by a circumplanetary disk. In addition, we added the companion-to-primary relative RV measurement to the orbital fitting and obtained updated constraints on orbital parameters. Detailed characterization of super-Jovian companions within 20 au like HIP 99770 b is critical for understanding the formation histories of this population.
Keywords
