J/AJ/168/295ivo://CDS.VizieR/J/AJ/168/295doi:10.26093/cds/vizier/be-58-97CDSZhang J.Huber D.Weiss L.M.Xuan J.W.Burt J.A.Dai F.Saunders N.,Petigura E.A.Rubenzahl R.A.Winn J.N.Wang S.X.Van Zandt J.,Brodheim M.Claytor Z.R.Crossfield I.Deich W.Fulton B.J.,Gibson S.R.Halverson S.Hill G.M.Holden B.Householder A.,Howard A.W.Isaacson H.Kaye S.Lanclos K.Laher R.R.Lubin J.,Payne J.Roy A.Schwab C.Shaum A.P.Walawender J.Wishnow E.,Yeh S.2026-07-02T11:45:12Z2025-09-19T14:30:26ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frexoplanetsradial-velocityvisible-astronomyspectroscopyCharacterizing 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_J_, a_c_=6.28_-0.11_^+0.10^AU) exterior to a close-in eccentric hot Jupiter HD 118203 b (P_b_=6.135d, m_b_=2.14+/-0.12M_J_, r_b_=1.14+/-0.029R_J_, e_b_=0.31+/-0.007) based on 20yr radial velocities (RVs). Using Rossiter-McLaughlin (RM) observations from the Keck Planet Finder, we measured a low sky-projected spin-orbit angle {lambda}_b_=-11.7{deg}_-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 {Psi}_b_<33.5{deg} (2{sigma}), 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 9.8{deg}_-9.3_^+16.2^ at the 2{sigma} 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 0.3-3.2AU for the proto-hot Jupiter.2024AJ....168..295Zhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/168/295CatalogResearchIsServedByTAP VizieR generic servicerelated-toII/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)J/ApJ/646/505 : Catalog of nearby exoplanets (Butler+, 2006)J/ApJ/723/L223 : Radial velocities of HAT-P-11 (Winn+, 2010)J/ApJ/757/18 : RVs for 16 hot Jupiter host stars (Albrecht+, 2012)J/ApJ/780/159 : Rot.-mass-age relationship of old field stars (Epstein+, 2014)J/ApJ/785/126 : HIRES radial velocity measurements (Knutson+, 2014)J/ApJ/821/89 : 12yrs of RVs obs. of exoplanet systems (Bryan+, 2016)J/ApJ/844/102 : KIC star plx from asteroseismology vs Gaia (Huber+, 2017)J/AJ/153/21 : Abund. in the local region. II. F, G, & K dwarfs (Luck+, 2017)J/ApJ/835/172 : Kepler asteroseismic LEGACY sample.I.Oscillations (Lund+, 2017)J/A+A/619/L10 : pi Men radial velocity curves (Gandolfi+, 2018)J/AJ/155/255 : RV and activity measurements of HAT-P-11 (Yee+, 2018)J/A+A/623/A72 : Binarity of HIP stars from Gaia pm anomaly (Kervella+, 2019)J/ApJS/241/12 : The Asteroseismic Target List (ATL) for TESS (Schofield+, 2019)J/AJ/159/243 : Light curve of HD 118203 b from TESS (Pepper+, 2020)J/AJ/159/280 : Gaia-Kepler stellar properties cat.I. KIC stars (Berger+, 2020)J/A+A/642/A31 : pi Men radial velocity curves (Damasso+, 2020)J/A+A/640/A73 : pi Men radial velocity curves (De Rosa+, 2020)J/A+A/640/A32 : WASP-148 velocity curve (Hebrard+, 2020)J/ApJS/254/42 : Hipparcos-Gaia (EDR3) Catalog of Accelerations (Brandt, 2021)J/AJ/162/89 : HIRES radial velocity follow up for Kepler-129 (Zhang+, 2021)J/ApJ/926/L8 : Spectroscopic and transit obs. of WASP-148 (Wang+, 2022)J/AJ/165/164 : Tull RVels, rotation periods and Inclinations (Bowler+, 2023)J/AJ/166/136 : HIRES/HARPS radial velocities for HAT-P-2 (de Beurs+, 2023)J/AJ/167/175 : Radial velocity and photometry of TOI-677 (Hu+, 2024)J/AJ/168/81 : TESS giants transiting giants. VI. Keck RVs (Saunders+, 2024)J/AJ/167/89 : Architect. of S* Transit. Planets in Binaries.I. (Zhang+, 2024)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/168/295https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/168/295http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/168/295https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/168/295https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/168/295http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/168/295GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/168/295/table1HD 118203 radial velocitiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJD[2455370/2503902] Barycentric Julian Date of observationdtime.epochdoubleRVel[-29640/172] Radial velocitym/sspect.dopplerVelocdoublee_RVel[0.6/28.4] Uncertainty in RVel (1)m/sstat.error;spect.dopplerVelocfloatInstInstrument used to get the RVel (2)instrcharRefReference for RVelmeta.refchar