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Published March 2021 | Accepted Version + Published
Journal Article Open

The McDonald Accelerating Stars Survey (MASS): White Dwarf Companions Accelerating the Sun-like Stars 12 Psc and HD 159062


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 M_B = 0.605^(+0.021)_(−0.022) M ⊙ 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 M_B = 0.609^(+0.010)_(−0.011) M⊙ 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 main-sequence companions.

Additional Information

© 2021 The American Astronomical Society. Received 2020 October 30; revised 2020 December 8; accepted 2020 December 8; published 2021 February 8. The authors are grateful to Michal Liu for the early NIRC2 imaging observations of 12 Psc in 2004 and 2005 as well as Keith Hawkins for helpful discussions about this system. We thank Diane Paulson, Rob Wittenmyer, Erik Brugamyer, Caroline Caldwell, Paul Robertson, Kevin Gullikson, and Marshall Johnson for contributing to the Tull observations of 12 Psc presented in this study. This work was supported by a NASA Keck PI Data Award, administered by the NASA Exoplanet Science Institute. Data presented herein were obtained at the W. M. Keck Observatory from telescope time allocated to the National Aeronautics and Space Administration through the agency's scientific partnership with the California Institute of Technology and the University of California. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. This research has made use of the Keck Observatory Archive (KOA), which is operated by the W. M. Keck Observatory and the NASA Exoplanet Science Institute (NExScI), under contract with the National Aeronautics and Space Administration. B.P.B. acknowledges support from the National Science Foundation grant AST-1909209. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Facilities: Smith (Tull Spectrograph) - , HET (HRS) - , Keck:II (NIRC2). -

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Accepted Version - 2012.04847.pdf

Published - Bowler_2021_AJ_161_106.pdf


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August 22, 2023
August 22, 2023