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Journal Articles The Astronomical Journal Year : 2019

Detection of a Low-mass Stellar Companion to the Accelerating A2IV Star HR 1645

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Robert J. de Rosa
  • Function : Author
Eric L. Nielsen
  • Function : Author
Alexandra Z. Greenbaum
  • Function : Author
Jason J. Wang
  • Function : Author
S. Mark Ammons
  • Function : Author
Vanessa P. Bailey
  • Function : Author
Travis Barman
  • Function : Author
Joanna Bulger
  • Function : Author
Jeffrey Chilcote
  • Function : Author
Tara Cotten
  • Function : Author
Rene Doyon
  • Function : Author
Thomas M. Esposito
  • Function : Author
Michael P. Fitzgerald
  • Function : Author
Katherine B. Follette
  • Function : Author
Benjamin L. Gerard
  • Function : Author
Stephen J. Goodsell
  • Function : Author
James R. Graham
  • Function : Author
Pascale Hibon
  • Function : Author
Justin Hom
  • Function : Author
Li-Wei Hung
  • Function : Author
Patrick Ingraham
  • Function : Author
Paul Kalas
  • Function : Author
Quinn Konopacky
  • Function : Author
James E. Larkin
  • Function : Author
Bruce Macintosh
  • Function : Author
Jérôme Maire
  • Function : Author
Franck Marchis
  • Function : Author
Mark S. Marley
  • Function : Author
Christian Marois
  • Function : Author
Stanimir Metchev
  • Function : Author
Maxwell A. Millar-Blanchaer
  • Function : Author
Rebecca Oppenheimer
  • Function : Author
David Palmer
  • Function : Author
Jennifer Patience
  • Function : Author
Marshall Perrin
  • Function : Author
Lisa Poyneer
  • Function : Author
Laurent Pueyo
  • Function : Author
Abhijith Rajan
  • Function : Author
Fredrik T. Rantakyrö
  • Function : Author
Bin Ren
  • Function : Author
Jean-Baptiste Ruffio
  • Function : Author
Dmitry Savransky
  • Function : Author
Adam C. Schneider
  • Function : Author
Anand Sivaramakrishnan
  • Function : Author
Inseok Song
  • Function : Author
Remi Soummer
  • Function : Author
Melisa Tallis
  • Function : Author
Sandrine Thomas
  • Function : Author
J. Kent Wallace
  • Function : Author
Kimberly Ward-Duong
  • Function : Author
Sloane Wiktorowicz
  • Function : Author
Schuyler Wolff
  • Function : Author

Abstract

The ∼500 Myr A2IV star HR 1645 has one of the most significant low-amplitude accelerations of nearby early-type stars measured from a comparison of the Hipparcos and Gaia astrometric catalogs. This signal is consistent with either a stellar companion with a moderate mass ratio (q ∼ 0.5) on a short period (P < 1 yr), or a substellar companion at a separation wide enough to be resolved with ground-based high-contrast imaging instruments; long-period equal-mass ratio stellar companions that are also consistent with the measured acceleration are excluded with previous imaging observations. The small but significant amplitude of the acceleration made HR 1645 a promising candidate for targeted searches for brown dwarf and planetary-mass companions around nearby, young stars. In this paper we explore the origin of the astrometric acceleration by modeling the signal induced by a wide-orbit M8 companion discovered with the Gemini Planet Imager, as well as the effects of an inner short-period spectroscopic companion discovered a century ago but not since followed up. We present the first constraints on the orbit of the inner companion, and demonstrate that it is a plausible cause of the astrometric acceleration. This result demonstrates the importance of vetting of targets with measured astrometric acceleration for short-period stellar companions prior to conducting targeted direct imaging surveys for wide-orbit substellar companions.

Dates and versions

insu-03699406 , version 1 (20-06-2022)

Identifiers

Cite

Robert J. de Rosa, Eric L. Nielsen, Julien Rameau, Gaspard Duchêne, Alexandra Z. Greenbaum, et al.. Detection of a Low-mass Stellar Companion to the Accelerating A2IV Star HR 1645. The Astronomical Journal, 2019, 158, ⟨10.3847/1538-3881/ab4ef7⟩. ⟨insu-03699406⟩
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