The Astronomical Journal (Jan 2023)
Astrometric Accelerations as Dynamical Beacons: Discovery and Characterization of HIP 21152 B, the First T-dwarf Companion in the Hyades
- Kyle Franson,
- Brendan P. Bowler,
- Mariangela Bonavita,
- Timothy D. Brandt,
- Minghan Chen,
- Matthias Samland,
- Zhoujian Zhang,
- Anna Lueber,
- Kevin Heng,
- Daniel Kitzmann,
- Trevor Wolf,
- Brandon A. Jones,
- Quang H. Tran,
- Daniella C. Bardalez Gagliuffi,
- Beth Biller,
- Jeffrey Chilcote,
- Justin R. Crepp,
- Trent J. Dupuy,
- Jacqueline Faherty,
- Clémence Fontanive,
- Tyler D. Groff,
- Raffaele Gratton,
- Olivier Guyon,
- Rebecca Jensen-Clem,
- Nemanja Jovanovic,
- N. Jeremy Kasdin,
- Julien Lozi,
- Eugene A. Magnier,
- Koraljka Mužić,
- Aniket Sanghi,
- Christopher A. Theissen
Affiliations
- Kyle Franson
- ORCiD
- Department of Astronomy, The University of Texas at Austin , Austin, TX 78712, USA ; [email protected]
- Brendan P. Bowler
- ORCiD
- Department of Astronomy, The University of Texas at Austin , Austin, TX 78712, USA ; [email protected]
- Mariangela Bonavita
- ORCiD
- School of Physical Sciences, The Open University , Walton Hall, Milton Keynes, MK7 6AA, UK
- Timothy D. Brandt
- ORCiD
- Department of Physics, University of California, Santa Barbara , Santa Barbara, CA 93106, USA
- Minghan Chen
- ORCiD
- Department of Physics, University of California, Santa Barbara , Santa Barbara, CA 93106, USA
- Matthias Samland
- ORCiD
- Max-Planck-Institut für Astronomie , Königstuhl 17, D-69117 Heidelberg, Germany
- Zhoujian Zhang
- ORCiD
- Department of Astronomy, The University of Texas at Austin , Austin, TX 78712, USA ; [email protected]
- Anna Lueber
- ORCiD
- Center for Space and Habitability, University of Bern , Gesellschaftsstrasse 6, 3012 Bern, Switzerland; Ludwig Maximilian University , University Observatory Munich, Scheinerstr. 1, Munich D-81679, Germany
- Kevin Heng
- ORCiD
- Center for Space and Habitability, University of Bern , Gesellschaftsstrasse 6, 3012 Bern, Switzerland; Ludwig Maximilian University , University Observatory Munich, Scheinerstr. 1, Munich D-81679, Germany; Department of Physics, Astronomy & Astrophysics Group, University of Warwick , Coventry, CV4 7AL, UK
- Daniel Kitzmann
- ORCiD
- Center for Space and Habitability, University of Bern , Gesellschaftsstrasse 6, 3012 Bern, Switzerland
- Trevor Wolf
- ORCiD
- Department of Aerospace Engineering and Engineering Mechanics, The University of Texas at Austin , Austin, TX 78712, USA
- Brandon A. Jones
- ORCiD
- Department of Aerospace Engineering and Engineering Mechanics, The University of Texas at Austin , Austin, TX 78712, USA
- Quang H. Tran
- ORCiD
- Department of Astronomy, The University of Texas at Austin , Austin, TX 78712, USA ; [email protected]
- Daniella C. Bardalez Gagliuffi
- ORCiD
- American Museum of Natural History , 200 Central Park West, New York, NY 10024, USA
- Beth Biller
- ORCiD
- SUPA, Institute for Astronomy, The University of Edinburgh , Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK
- Jeffrey Chilcote
- Department of Physics, University of Notre Dame , 225 Nieuwland Science Hall, Notre Dame, IN 46556, USA
- Justin R. Crepp
- ORCiD
- Department of Physics, University of Notre Dame , 225 Nieuwland Science Hall, Notre Dame, IN 46556, USA
- Trent J. Dupuy
- ORCiD
- Institute for Astronomy, University of Edinburgh , Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK
- Jacqueline Faherty
- ORCiD
- American Museum of Natural History , 200 Central Park West, New York, NY 10024, USA
- Clémence Fontanive
- ORCiD
- Center for Space and Habitability, University of Bern , Gesellschaftsstrasse 6, 3012 Bern, Switzerland
- Tyler D. Groff
- ORCiD
- NASA-Goddard Space Flight Center , Greenbelt, MD 20771, USA
- Raffaele Gratton
- ORCiD
- INAF Osservatorio Astronomico di Padova , Vicolo dell’Osservatorio 5, I-35121 Padova, Italy
- Olivier Guyon
- ORCiD
- Subaru Telescope, National Astronomical Observatory of Japan , 650 North A‘ohōkū Place, Hilo, HI 96720, USA; Steward Observatory, University of Arizona , Tucson, AZ 85721, USA; Astrobiology Center of NINS , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
- Rebecca Jensen-Clem
- ORCiD
- Astronomy & Astrophysics Department, University of California, Santa Cruz , CA 95064, USA
- Nemanja Jovanovic
- ORCiD
- Department of Astronomy, California Institute of Technology , 1200 East California Boulevard, Pasadena, CA 91125, USA
- N. Jeremy Kasdin
- ORCiD
- Department of Mechanical Engineering, Princeton University , Princeton, NJ 08544-5263, USA
- Julien Lozi
- ORCiD
- Subaru Telescope, National Astronomical Observatory of Japan , 650 North A‘ohōkū Place, Hilo, HI 96720, USA
- Eugene A. Magnier
- ORCiD
- Institute for Astronomy, University of Hawai‘i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA
- Koraljka Mužić
- ORCiD
- CENTRA, Faculdade de Ciências, Universidade de Lisboa , Ed. C8, Campo Grande, P-1749-016 Lisboa, Portugal
- Aniket Sanghi
- ORCiD
- Department of Astronomy, The University of Texas at Austin , Austin, TX 78712, USA ; [email protected]
- Christopher A. Theissen
- ORCiD
- Center for Astrophysics and Space Sciences, University of California, San Diego , 9500 Gilman Drive, La Jolla, CA 92093, USA
- DOI
- https://doi.org/10.3847/1538-3881/aca408
- Journal volume & issue
-
Vol. 165,
no. 2
p. 39
Abstract
Benchmark brown dwarf companions with well-determined ages and model-independent masses are powerful tools to test substellar evolutionary models and probe the formation of giant planets and brown dwarfs. Here, we report the independent discovery of HIP 21152 B, the first imaged brown dwarf companion in the Hyades, and conduct a comprehensive orbital and atmospheric characterization of the system. HIP 21152 was targeted in an ongoing high-contrast imaging campaign of stars exhibiting proper-motion changes between Hipparcos and Gaia, and was also recently identified by Bonavita et al. (2022) and Kuzuhara et al. (2022). Our Keck/NIRC2 and SCExAO/CHARIS imaging of HIP 21152 revealed a comoving companion at a separation of 0.″37 (16 au). We perform a joint orbit fit of all available relative astrometry and radial velocities together with the Hipparcos-Gaia proper motions, yielding a dynamical mass of ${24}_{-4}^{+6}\,{M}_{\mathrm{Jup}}$ , which is 1–2 σ lower than evolutionary model predictions. Hybrid grids that include the evolution of cloud properties best reproduce the dynamical mass. We also identify a comoving wide-separation (1837″ or 7.9 × 10 ^4 au) early-L dwarf with an inferred mass near the hydrogen-burning limit. Finally, we analyze the spectra and photometry of HIP 21152 B using the Saumon & Marley (2008) atmospheric models and a suite of retrievals. The best-fit grid-based models have f _sed = 2, indicating the presence of clouds, T _eff = 1400 K, and $\mathrm{log}g=4.5\,\mathrm{dex}$ . These results are consistent with the object’s spectral type of T0 ± 1. As the first benchmark brown dwarf companion in the Hyades, HIP 21152 B joins the small but growing number of substellar companions with well-determined ages and dynamical masses.
Keywords
