The Astronomical Journal (Jan 2024)
A Testbed for Tidal Migration: The 3D Architecture of an Eccentric Hot Jupiter HD 118203 b Accompanied by a Possibly Aligned Outer Giant Planet
- Jingwen Zhang,
- Daniel Huber,
- Lauren M. Weiss,
- Jerry W. Xuan,
- Jennifer A. Burt,
- Fei Dai,
- Nicholas Saunders,
- Erik A. Petigura,
- Ryan A. Rubenzahl,
- Joshua N. Winn,
- Sharon X. Wang,
- Judah Van Zandt,
- Max Brodheim,
- Zachary R. Claytor,
- Ian Crossfield,
- William Deich,
- Benjamin J. Fulton,
- Steven R. Gibson,
- Samuel Halverson,
- Grant M. Hill,
- Bradford Holden,
- Aaron Householder,
- Andrew W. Howard,
- Howard Isaacson,
- Stephen Kaye,
- Kyle Lanclos,
- Russ R. Laher,
- Jack Lubin,
- Joel Payne,
- Arpita Roy,
- Christian Schwab,
- Abby P. Shaum,
- Josh Walawender,
- Edward Wishnow,
- Sherry Yeh
Affiliations
- Jingwen Zhang
- ORCiD
- Institute for Astronomy, University of Hawai’i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA ; [email protected]
- Daniel Huber
- ORCiD
- Institute for Astronomy, University of Hawai’i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA ; [email protected]; Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney , NSW 2006, Australia
- Lauren M. Weiss
- ORCiD
- Department of Physics and Astronomy, University of Notre Dame , Notre Dame, IN 46556, USA
- Jerry W. Xuan
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Jennifer A. Burt
- ORCiD
- Jet Propulsion Laboratory, California Institute of Technology , 4800 Oak Grove Drive, Pasadena, CA 91109, USA
- Fei Dai
- ORCiD
- Institute for Astronomy, University of Hawai’i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA ; [email protected]
- Nicholas Saunders
- ORCiD
- Institute for Astronomy, University of Hawai’i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA ; [email protected]
- Erik A. Petigura
- ORCiD
- Department of Physics & Astronomy, University of California Los Angeles , Los Angeles, CA 90095, USA
- Ryan A. Rubenzahl
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Joshua N. Winn
- ORCiD
- Department of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08540, USA
- Sharon X. Wang
- ORCiD
- Department of Astronomy, Tsinghua University , Beijing 100084, People's Republic of China
- Judah Van Zandt
- ORCiD
- Department of Physics & Astronomy, University of California Los Angeles , Los Angeles, CA 90095, USA
- Max Brodheim
- ORCiD
- W. M. Keck Observatory , 65-1120 Mamalahoa Highway, Kamuela, HI 96743, USA
- Zachary R. Claytor
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA; Department of Astronomy, University of Florida , 211 Bryant Space Science Center, Gainesville, FL 32611, USA
- Ian Crossfield
- Department of Physics and Astronomy, University of Kansas , Lawrence, KS, USA
- William Deich
- ORCiD
- UC Observatories, University of California , Santa Cruz, CA 95064, USA
- Benjamin J. Fulton
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Steven R. Gibson
- ORCiD
- Caltech Optical Observatories, California Institute of Technology , Pasadena, CA 91125, USA
- Samuel Halverson
- ORCiD
- Jet Propulsion Laboratory, California Institute of Technology , 4800 Oak Grove Drive, Pasadena, CA 91109, USA
- Grant M. Hill
- ORCiD
- W. M. Keck Observatory , 65-1120 Mamalahoa Highway, Kamuela, HI 96743, USA
- Bradford Holden
- ORCiD
- UC Observatories, University of California , Santa Cruz, CA 95064, USA
- Aaron Householder
- ORCiD
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology , Cambridge, MA 02139, USA; Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Andrew W. Howard
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Howard Isaacson
- ORCiD
- Department of Astronomy, 501 Campbell Hall, University of California , Berkeley, CA 94720, USA
- Stephen Kaye
- Caltech Optical Observatories, California Institute of Technology , Pasadena, CA 91125, USA
- Kyle Lanclos
- ORCiD
- W. M. Keck Observatory , 65-1120 Mamalahoa Highway, Kamuela, HI 96743, USA
- Russ R. Laher
- ORCiD
- NASA Exoplanet Science Institute/Caltech-IPAC, MC 314-6, 1200 E California Boulevard, Pasadena, CA 91125, USA
- Jack Lubin
- ORCiD
- Department of Physics & Astronomy, University of California Los Angeles , Los Angeles, CA 90095, USA
- Joel Payne
- ORCiD
- W. M. Keck Observatory , 65-1120 Mamalahoa Highway, Kamuela, HI 96743, USA
- Arpita Roy
- ORCiD
- Astrophysics & Space Institute , Schmidt Sciences, New York, NY 10011, USA
- Christian Schwab
- ORCiD
- School of Mathematical and Physical Sciences, Macquarie University , Balaclava Road, North Ryde, NSW 2109, Australia
- Abby P. Shaum
- ORCiD
- Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Josh Walawender
- ORCiD
- W. M. Keck Observatory , 65-1120 Mamalahoa Highway, Kamuela, HI 96743, USA
- Edward Wishnow
- Space Sciences Laboratory, University of California , Berkeley, CA 94720, USA
- Sherry Yeh
- ORCiD
- W. M. Keck Observatory , 65-1120 Mamalahoa Highway, Kamuela, HI 96743, USA
- DOI
- https://doi.org/10.3847/1538-3881/ad86c4
- Journal volume & issue
-
Vol. 168,
no. 6
p. 295
Abstract
Characterizing outer companions to hot Jupiters plays a crucial role in deciphering their origins. We present the discovery of a long-period giant planet, HD 118203 c ( ${m}_{c}={11.79}_{-0.63}^{+0.69}\ {M}_{{\rm{J}}}$ , ${a}_{c}={6.28}_{-0.11}^{+0.10}$ au) exterior to a close-in eccentric hot Jupiter HD 118203 b ( P _b = 6.135 days, m _b = 2.14 ± 0.12 M _J , r _b = 1.14 ± 0.029 R _J , e _b = 0.31 ± 0.007) based on 20 yr radial velocities (RVs). Using Rossiter–McLaughlin (RM) observations from the Keck Planet Finder, we measured a low sky-projected spin–orbit angle ${\lambda }_{b}=-11^\circ {7}_{-10.0}^{+7.6}$ for HD 118203 b and detected stellar oscillations in the host star, confirming its evolved status. Combining the RM observation with the stellar inclination measurement, we constrained the true spin–orbit angle of HD 118203 b as Ψ _b < 33.°5 (2 σ ), indicating the orbit normal of the hot Jupiter nearly aligned with the stellar spin axis. Furthermore, by combining RVs and Hipparcos-Gaia astrometric acceleration, we constrained the line-of-sight mutual inclination between the hot Jupiter and the outer planet to be $9\buildrel{\circ}\over{.} {8}_{-9.3}^{+16.2}$ at the 2 σ level. HD 118203 is one of first hot Jupiter systems where both the true spin–orbit angle of the hot Jupiter and the mutual inclination between inner and outer planets have been determined. Our results are consistent with a system-wide alignment, with low mutual inclinations between the outer giant planet, the inner hot Jupiter, and the host star. This alignment, along with the moderate eccentricity of HD 118203 c, implies that the system may have undergone coplanar high-eccentricity tidal migration. Under this framework, our dynamical analysis suggests an initial semimajor axis of 0.3–3.2 au for the proto–hot Jupiter.
Keywords
