The McDonald accelerating stars survey (MASS): White dwarf companions accelerating the sun-like stars 12 Psc and HD 159062

Brendan P. Bowler, William D. Cochran, Michael Endl, Kyle Franson, Timothy D. Brandt, Trent J. Dupuy, Phillip J. MacQueen, Kaitlin M. Kratter, Dimitri Mawet, Garreth Ruane

Research output: Contribution to journalArticlepeer-review

Abstract

We present the discovery of a white dwarf companion to the G1 V star 12 Psc found as part of a Keck adaptive optics imaging survey of long-term accelerating stars from the McDonald Observatory Planet Search Program. Twenty years of precise radial-velocity monitoring of 12 Psc with the Tull Spectrograph at the Harlan J. Smith telescope reveals a moderate radial acceleration (~10 m s-1 yr -1), which together with relative astrometry from Keck/NIRC2 and the astrometric acceleration between Hipparcos and Gaia DR2 yields a dynamical mass of MB =0.605+0.021-0.022M⊙ for 12 Psc B, a semimajor axis of 40+2-4 au, and an eccentricity of 0.84 ± 0.08. We also report an updated orbital fit of the white dwarf companion to the metal-poor (but barium-rich) G9 V dwarf HD 159062 based on new radial-velocity observations from the High-Resolution Spectrograph at the Hobby-Eberly Telescope and astrometry from Keck/NIRC2. A joint fit of the available relative astrometry, radial velocities, and tangential astrometric acceleration yields a dynamical mass of MB = 0.609+0.010-0.011M⊙ for HD 159062 B, a semimajor axis of 60+5-7 au, and preference for circular orbits (e < 0.42 at 95% confidence). 12 Psc B and HD 159062 B join a small list of resolved Sirius-like benchmark white dwarfs with precise dynamical mass measurements which serve as valuable tests of white dwarf mass-radius cooling models and probes of AGB wind accretion onto their mainsequence companions.

Original languageEnglish (US)
Article numberabd243
JournalAstronomical Journal
Volume161
Issue number3
DOIs
StatePublished - Mar 1 2021

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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