Direct Imaging Discovery and Dynamical Mass of a Substellar Companion Orbiting an Accelerating Hyades Sun-like Star with SCExAO/CHARIS

Abstract

We present the direct-imaging discovery of a substellar companion in orbit around a Sun-like star member of the Hyades open cluster. So far, no other substellar companions have been unambiguously confirmed via direct imaging around main-sequence stars in Hyades. The star HIP 21152 is an accelerating star as identified by the astrometry from the Gaia and Hipparcos satellites. We have detected the companion, HIP 21152 B, in multi-epoch using the high-contrast imaging from SCExAO/CHARIS and Keck/NIRC2. We have also obtained the stellar radial-velocity data from the Okayama 188cm telescope. The CHARIS spectroscopy reveals that HIP 21152 B's spectrum is consistent with the L/T transition, best fit by an early T dwarf. Our orbit modeling determines the semi-major axis and the dynamical mass of HIP 21152 B to be 17.5${}_{-3.8}^{+7.2}$ au and 27.8${}_{-5.4}^{+8.4}$ $M_{\mathrm{Jup}}$, respectively. The mass ratio of HIP 21152 B relative to its host is $\approx$2\%, near the planet/brown dwarf boundary suggested from recent surveys. Mass estimates inferred from luminosity evolution models are slightly higher (33--42 $M_{\mathrm{Jup}}$). With a dynamical mass and a well-constrained age due to the system's Hyades membership, HIP 21152 B will become a critical benchmark in understanding the formation, evolution, and atmosphere of a substellar object as a function of mass and age. Our discovery is yet another key proof-of-concept for using precision astrometry to select direct imaging targets.

21 pages (11 pages in main body), 8 figures (4 figures in main body). Accepted for Publication in ApJL at July 9, 2022 (UT)

References in corpus (28)

• The NumPy array: a structure for efficient numerical computation
• The Gaia mission
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
• The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics From 10-100 AU
• The 0.8-14.5 micron Spectra of Mid-L to Mid-T Dwarfs: Diagnostics of Effective Temperature, Grain Sedimentation, Gas Transport, and Surface Gravity
• Fundamental limitations of high contrast imaging set by small sample statistics
• The Hipparcos-Gaia Catalog of Accelerations: Gaia EDR3 Edition
• The Hawaii Infrared Parallax Program. II. Young Ultracool Field Dwarfs
• Mapping the Shores of the Brown Dwarf Desert I.: Upper Scorpius
• Planets Around Low-Mass Stars (PALMS). IV. The Outer Architecture of M Dwarf Planetary Systems
• The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets
• Characterizing 51 Eri b from 1-5 $\mu$m: a partly-cloudy exoplanet
• Bayesian Ages for Early-Type Stars from Isochrones Including Rotation, and a Possible Old Age for the Hyades
• orvara: An Efficient Code to Fit Orbits using Radial Velocity, Absolute, and/or Relative Astrometry
• A Volume-Limited Sample of Ultracool Dwarfs. I. Construction, Space Density, and a Gap in the L/T Transition
• Deep Thermal Infrared Imaging of HR 8799 bcde: New Atmospheric Constraints and Limits on a Fifth Planet
• New Evidence for a Substellar Luminosity Problem: Dynamical Mass for the Brown Dwarf Binary Gl 417BC
• A 3D view of the Hyades stellar and sub-stellar population
• SCExAO/CHARIS Direct Imaging Discovery of a 20 au Separation, Low-Mass Ratio Brown Dwarf Companion to an Accelerating Sun-like Star
• New HST data and modeling reveal a massive planetesimal collision around Fomalhaut
• A Brown Dwarf Census from the SIMP Survey
• Dynamical Mass of the Young Substellar Companion HD 984 B
• Evolutionary models for ultracool dwarfs
• Results from The COPAINS Pilot Survey: four new brown dwarfs and a high companion detection rate for accelerating stars
• Bayesian calibration of the mixing length parameter ${\alpha }_{ML}$ and of the helium-to-metal enrichment ratio $\Delta Y/\Delta Z$ with open clusters: the Hyades test-bed
• The McDonald Accelerating Stars Survey (MASS): Discovery of a Long-Period Substellar Companion Orbiting the Old Solar Analog HD 47127

Cited by in corpus (37)

• Direct discovery of the inner exoplanet in the HD206893 system. Evidence for deuterium burning in a planetary-mass companion
• Direct imaging discovery of a super-Jovian around the young Sun-like star AF Leporis
• Direct Imaging and Astrometric Detection of a Gas Giant Planet Orbiting an Accelerating Star
• Bosonic Dark Matter in Light of the NICER Precise Mass-Radius Measurements
• Rotation Periods, Inclinations, and Obliquities of Cool Stars Hosting Directly Imaged Substellar Companions: Spin-Orbit Misalignments are Common
• What neutron stars tell about the hadron-quark phase transition: a Bayesian study
• Tidal Deformability of Fermion-Boson Stars: Neutron Stars Admixed with Ultra-Light Dark Matter
• Astrometric Accelerations as Dynamical Beacons: Discovery and Characterization of HIP 21152 B, the First T-Dwarf Companion in the Hyades
• Inflationary Attractors Predictions for Static Neutron Stars in the Mass-Gap Region
• ISPY-NACO Imaging Survey for Planets around Young stars. The demographics of forming planets embedded in protoplanetary disks
• Hybrid stars are compatible with recent astrophysical observations
• Surveying Nearby Brown Dwarfs with HGCA: Direct Imaging Discovery of a Faint, High-Mass Brown Dwarf Orbiting HD 176535 A
• Central Speed of Sound, Trace Anomaly and Observables of Neutron Stars from Perturbative Analyses of Scaled TOV Equations
• Redder than Red: Discovery of an Exceptionally Red L/T Transition Dwarf
• Precise dynamical masses of new directly imaged companions from combining relative astrometry, radial velocities, and Hipparcos-Gaia eDR3 accelerations
• Direct-imaging Discovery of a Substellar Companion Orbiting the Accelerating Variable Star, HIP 39017
• Dynamical Mass of the Young Brown Dwarf Companion PZ Tel B
• A Bayesian study of quark models in view of recent astrophysical constraints
• The COBREX archival survey: improved constraints on the occurrence rate of wide-orbit substellar companions. I. A uniform re-analysis of 400 stars from the GPIES survey
• Multi techniques approach to identify and/or constrain radial velocity sub-stellar companions
• Vortex Fiber Nulling for Exoplanet Observations: Implementation and First Light
• SCExAO and Keck Direct Imaging Discovery of a Low-Mass Companion Around the Accelerating F5 Star HIP 5319
• Hybrid stars may have an inverted structure
• Exploring the directly imaged HD 1160 system through spectroscopic characterization and high-cadence variability monitoring
• The McDonald Accelerating Stars Survey (MASS): Architecture of the Ancient Five-Planet Host System Kepler-444
• A catalog of nearby accelerating star candidates in Gaia DR3
• A study of the frequency and characteristics of stellar companions and Jupiter-like planets in nearby open clusters
• Post-processing CHARIS integral field spectrograph data with PyKLIP
• Correlating Intrinsic Stellar Parameters with Mg II Self-Reversal Depths
• Distinct Rotational Evolution of Giant Planets and Brown Dwarf Companions
• Probing into the Possible Range of the U Bosonic Coupling Constants in Neutron Stars Containing Hyperons
• Spectroscopy using a visible photonic lantern at the Subaru telescope: Laboratory characterization and first on-sky demonstration on Ikiiki (α Leo) and `Aua (α Ori)
• Weighing the Darkness III: How Gaia Could, but Probably Won't, Astrometrically Detect Free-Floating Black Holes
• SCExAO/CHARIS and Gaia Direct Imaging and Astrometric Discovery of a Superjovian Planet 3--4 lambda/D from the Accelerating Star HIP 54515
• OASIS Survey Direct Imaging and Astrometric Discovery of HIP 71618 B: A Substellar Companion Suitable for the Roman Coronagraph Technology Demonstration
• Apache Point Observatory follow-up of ACcelerating Candidate ExopLanet host Stars (APO ACCELS): Ages for 166 Accelerating Stars in the Northern Hemisphere
• SCExAO/CHARIS Multi-Wavelength, High-Contrast Imaging of the BD+45${}^{\circ }$598 Debris Disk