The Astronomical Journal (Jan 2024)
κ Andromedae b Is a Fast Rotator from KPIC High-resolution Spectroscopy
- Evan C. Morris,
- Jason J. Wang,
- Chih-Chun Hsu,
- Jean-Baptiste Ruffio,
- Jerry W. Xuan,
- Jacques-Robert Delorme,
- Callie Hood,
- Marta L. Bryan,
- Emily C. Martin,
- Jacklyn Pezzato,
- Dimitri Mawet,
- Andrew Skemer,
- Ashley Baker,
- Randall Bartos,
- Benjamin Calvin,
- Sylvain Cetre,
- Greg Doppmann,
- Daniel Echeverri,
- Luke Finnerty,
- Michael P. Fitzgerald,
- Nemanja Jovanovic,
- Joshua Liberman,
- Ronald Lopez,
- Ben Sappey,
- Tobias Schofield,
- J. Kent Wallace,
- Ji Wang
Affiliations
- Evan C. Morris
- ORCiD
- Department of Astronomy & Astrophysics, University of California , Santa Cruz, CA 95064, USA ; [email protected]
- Jason J. Wang
- ORCiD
- Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University , 1800 Sherman, Evanston, IL 9 60201, USA
- Chih-Chun Hsu
- ORCiD
- Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University , 1800 Sherman, Evanston, IL 9 60201, USA
- Jean-Baptiste Ruffio
- ORCiD
- Center for Astrophysics and Space Sciences, University of California , San Diego, La Jolla, CA 92093, USA
- Jerry W. Xuan
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Jacques-Robert Delorme
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA; W. M. Keck Observatory , 65-1120 Mamalahoa Highway, Kamuela, HI, USA
- Callie Hood
- ORCiD
- Department of Astronomy & Astrophysics, University of California , Santa Cruz, CA 95064, USA ; [email protected]
- Marta L. Bryan
- ORCiD
- David A. Dunlap Institute Department of Astronomy & Astrophysics, University of Toronto , 50 St. George Street, Toronto, ON M5S 3H4, Canada
- Emily C. Martin
- ORCiD
- Department of Astronomy & Astrophysics, University of California , Santa Cruz, CA 95064, USA ; [email protected]
- Jacklyn Pezzato
- 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
- Andrew Skemer
- ORCiD
- Department of Astronomy & Astrophysics, University of California , Santa Cruz, CA 95064, USA ; [email protected]
- Ashley Baker
- ORCiD
- 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
- 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 Highway, Kamuela, HI, USA
- Greg Doppmann
- W. M. Keck Observatory , 65-1120 Mamalahoa Highway, 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
- James C. Wyant College of Optical Sciences, University of Arizona , Meinel Building 1630 E. University Boulevard, Tucson, AZ 85721, USA
- Ronald Lopez
- ORCiD
- Department of Physics & Astronomy, 430 Portola Plaza, University of California , Los Angeles, CA 90095, USA
- Ben Sappey
- ORCiD
- Center for Astrophysics and Space Sciences, University of California , San Diego, La Jolla, CA 92093, USA
- Tobias Schofield
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, 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
- DOI
- https://doi.org/10.3847/1538-3881/ad4ecf
- Journal volume & issue
-
Vol. 168,
no. 4
p. 144
Abstract
We used the Keck Planet Imager and Characterizer to obtain high-resolution ( R ∼ 35,000) K -band spectra of κ Andromedae b, a planetary-mass companion orbiting the B9V star, κ Andromedae A. We characterized its spin, radial velocity, and bulk atmospheric parameters through use of a forward-modeling framework to jointly fit planetary spectra and residual starlight speckles, obtaining likelihood-based posterior probabilities. We also detected H _2 O and CO in its atmosphere via cross correlation. We measured a $v\sin (i)$ value for κ Andromedae b of 38.42 ± 0.05 km s ^−1 , allowing us to extend our understanding of the population of close-in bound companions at higher rotation rates. This rotation rate is one of the highest spins relative to breakup velocity measured to date, at close to 50% of breakup velocity. We identify a radial velocity $-{17.35}_{-0.09}^{+0.05}$ km s ^−1 , which we use with existing astrometry and radial velocity measurements to update the orbital fit. We also measure an effective temperature of 1700 ± 100 K and a $\mathrm{log}(g)$ of 4.7 ± 0.5 cgs dex.
Keywords
