Direct-imaging Discovery and Dynamical Mass of a Substellar Companion Orbiting an Accelerating Hyades Sun-like Star with SCExAO/CHARIS - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles The Astrophysical journal letters Year : 2022

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

Masayuki Kuzuhara
  • Function : Author
Thayne Currie
  • Function : Author
Takuya Takarada
  • Function : Author
Timothy D. Brandt
  • Function : Author
Bun'Ei Sato
  • Function : Author
Taichi Uyama
  • Function : Author
Markus Janson
  • Function : Author
Jeffrey Chilcote
  • Function : Author
Taylor Tobin
  • Function : Author
Kellen Lawson
  • Function : Author
Yasunori Hori
  • Function : Author
Olivier Guyon
  • Function : Author
Tyler D. Groff
  • Function : Author
Julien Lozi
  • Function : Author
Sebastien Vievard
  • Function : Author
Ananya Sahoo
  • Function : Author
Vincent Deo
  • Function : Author
Nemanja Jovanovic
  • Function : Author
Kyohoon Ahn
  • Function : Author
Eiji Akiyama
  • Function : Author
Barnaby R. Norris
  • Function : Author
Krzysztof G. Hełminiak
  • Function : Author
Tomoyuki Kudo
  • Function : Author
Michael W. Mcelwain
  • Function : Author
Matthias Samland
  • Function : Author
Kevin Wagner
  • Function : Author
John Wisniewski
  • Function : Author
Gillian R. Knapp
  • Function : Author
Jungmi Kwon
  • Function : Author
Jun Nishikawa
  • Function : Author
Eugene Serabyn
  • Function : Author
Masahiko Hayashi
  • Function : Author
Motohide Tamura
  • Function : Author

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 detected the companion, HIP 21152 B, in multiple epochs using the high-contrast imaging from SCExAO/CHARIS and Keck/NIRC2. We also obtained the stellar radial-velocity data from the Okayama 188 cm 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 semimajor 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 Jup, respectively. The mass ratio of HIP 21152 B relative to its host is ≍2%, near the planet/brown dwarf boundary suggested by recent surveys. Mass estimates inferred from luminosity-evolution models are slightly higher (33-42 M 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. *Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.
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insu-03860316 , version 1 (18-11-2022)

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Masayuki Kuzuhara, Thayne Currie, Takuya Takarada, Timothy D. Brandt, Bun'Ei Sato, et al.. Direct-imaging Discovery and Dynamical Mass of a Substellar Companion Orbiting an Accelerating Hyades Sun-like Star with SCExAO/CHARIS. The Astrophysical journal letters, 2022, 934, ⟨10.3847/2041-8213/ac772f⟩. ⟨insu-03860316⟩
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