The Mass of HD 38529 c from Hubble Space Telescope Astrometry and High-Precision Radial Velocities

Abstract

(Abridged) Hubble Space Telescope (HST) Fine Guidance Sensor astrometric observations of the G4 IV star HD 38529 are combined with the results of the analysis of extensive ground-based radial velocity data to determine the mass of the outermost of two previously known companions. Our new radial velocities obtained with the Hobby-Eberly Telescope and velocities from the Carnegie-California group now span over eleven years. With these data we obtain improved RV orbital elements for both the inner companion, HD 38529 b and the outer companion, HD 38529 c. We identify a rotational period of HD 38529 (P_{rot}=31.65 +/- 0.17 d) with FGS photometry. We model the combined astrometric and RV measurements to obtain the parallax, proper motion, perturbation period, perturbation inclination, and perturbation size due to HD 38529 c. For HD 38529 c we find P = 2136.1 +/- 0.3 d, perturbation semi-major axis α=1.05 +/-0.06$mas,andinclination$i$=48.3deg+/-4deg.Assumingaprimarymass{M}_{\ast }=1.48M_{sun},weobtainacompanionmass{M}_c=17.6_{-1.2}^{+1.5}{M}_{Jup},3-sigmaabovea13M_{Jup}deuteriumburning,browndwarflowerlimit.DynamicalsimulationsincorporatingthisaccuratemassforHD38529cindicatethatanear-Saturnmassplanetcouldexistbetweenthetwoknowncompanions.Wefindweakevidenceofanadditionallowamplitudesignalthatcanbemodeledasaplanetary-mass(0.17M$_{Jup}) companion at P~194 days. Additional observations (radial velocities and/or Gaia astrometry) are required to validate an interpretation of HD 38529 d as a planetary-mass companion. If confirmed, the resulting HD 38529 planetary system may be an example of a "Packed Planetary System".

Accepted by The Astronomical Journal

References in corpus (15)

• Stellar SEDs from 0.3-2.5 Microns: Tracing the Stellar Locus and Searching for Color Outliers in SDSS and 2MASS
• Structure and Evolution of Nearby Stars with Planets II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog
• Transiting exoplanets from the CoRoT space mission VI. CoRoT-Exo-3b: The first secure inhabitant of the brown-dwarf desert
• Cepheid Parallaxes and the Hubble Constant
• The Extrasolar Planet epsilon Eridani b - Orbit and Mass
• Double-blind test program for astrometric planet detection with Gaia
• CHARA Array Measurements of the Angular Diameters of Exoplanet Host Stars
• Planet-planet scattering leads to tightly packed planetary systems
• A Search for Multi-Planet Systems Using the Hobby-Eberly Telescope
• The Mass of the Candidate Exoplanet Companion to HD 33636 from Hubble Space Telescope Astrometry and High-Precision Radial Velocities
• Calibrated griz magnitudes of Tycho stars: All-sky photometric calibration using bright stars
• The dust, planetesimals and planets of HD 38529
• Detection of a Third Planet in the HD 74156 System Using the Hobby-Eberly Telescope
• The Mass of the Candidate Exoplanet Companion to HD136118 from Hubble Space Telescope Astrometry and High-Precision Radial Velocities
• The Search for Stellar Companions to Exoplanet Host Stars Using the CHARA Array

Cited by in corpus (37)

• Search for brown-dwarf companions of stars
• Statistical Properties of Brown Dwarf Companions: Implications for Different Formation Mechanisms
• Amplitudes of solar-like oscillations: a new scaling relation
• Distance Scale Zero-Points from Galactic RR Lyrae Star Parallaxes
• Mass constraints on substellar companion candidates from the re-reduced Hipparcos intermediate astrometric data: Nine confirmed planets and two confirmed brown dwarfs
• The Dynamical Mass and Three-Dimensional Orbit of HR7672B: A Benchmark Brown Dwarf with High Eccentricity
• 3-D selection of 167 sub-stellar companions to nearby stars
• Substellar-Mass Companions to the K-Giants HD 240237, BD +48 738 and HD 96127
• Calibrating the metallicity of M dwarfs in wide physical binaries with F-, G-, and K- primaries - I: High-resolution spectroscopy with HERMES: stellar parameters, abundances, and kinematics
• The SOPHIE search for northern extrasolar planets IX. Populating the brown dwarf desert
• Astrometry with Hubble Space Telescope Fine Guidance Sensors - A Review
• Host Star Properties and Transit Exclusion for the HD 38529 Planetary System
• Determining the true mass of radial-velocity exoplanets with Gaia: 9 planet candidates in the brown-dwarf/stellar regime and 27 confirmed planets
• Astrometry with the Hubble Space Telescope: Trigonometric Parallaxes of Selected Hyads
• HST Fine Guidance Sensor Parallaxes for Four Classical Novae
• The mass of planet GJ676A b from ground-based astrometry: A planetary system with two mature gas giants suitable for direct imaging
• The Masses of a Sample of Radial-Velocity Exoplanets with Astrometric Measurements
• HD 5388 b is a 69 M_Jup companion instead of a planet
• HD 202206 : A Circumbinary Brown Dwarf System
• Updated characterization of long-period single companion by combining radial velocity, relative astrometry, and absolute astrometry
• Tidal damping of the mutual inclination in hierachical systems
• Analysis of radial velocity variations in multiple planetary systems
• Astrometric planet search around southern ultracool dwarfs II: Astrometric reduction methods and a deep astrometric catalogue
• Parallax of the L4.5 dwarf 2M1821$+$14 from high-precision astrometry with OSIRIS at GTC
• Robust asteroseismic properties of the bright planet host HD 38529
• The SOPHIE search for northern extrasolar planets - XII. Three giant planets suitable for astrometric mass determination with Gaia
• The ESPRI project: astrometric exoplanet search with PRIMA I. Instrument description and performance of first light observations
• Mutual inclinations between giant planets and their debris discs in HD 113337 and HD 38529
• Luminaries in the Sky: The TESS Legacy Sample of Bright Stars. I. Asteroseismic detections in naked-eye main-sequence and sub-giant solar-like oscillators
• A possible dividing line between massive planets and brown-dwarf companions
• Enabling science with Gaia observations of naked-eye stars
• The mu Arae planetary system: Radial velocities and astrometry
• The 14 Her Planetary System: Companion Masses and Architecture from Radial Velocities and Astrometry
• Future Astrometric Space Missions for Exoplanet Science
• HD 28185 Revisited: An Outer Planet, Instead of a Brown Dwarf, On a Saturn-like Orbit
• Detection of a low-mass stellar companion to the accelerating A2IV star HR 1645
• ROME IV. The Arecibo Search for Substellar Magnetospheric Radio Emissions in Purported Exoplanet-Hosting Systems at 5 GHz