Discovery of a White Dwarf Companion to HD 159062

June 2019 • 2019ApJ...878...50H

Authors • Hirsch, Lea A. • Ciardi, David R. • Howard, Andrew W. • Marcy, Geoffrey W. • Ruane, Garreth • Gonzalez, Erica • Blunt, Sarah • Crepp, Justin R. • Fulton, Benjamin J. • Isaacson, Howard • Kosiarek, Molly • Mawet, Dimitri • Sinukoff, Evan • Weiss, Lauren

Abstract • We report on the discovery of a white dwarf companion to the nearby late G dwarf star, HD 159062. The companion is detected in 14 years of precise radial velocity (RV) data, and in high-resolution imaging observations. RVs of HD 159062 from 2003 to 2018 reveal an acceleration of -13.3 ± 0.12 {{m}} {{{s}}}^-1 {yr}}^-1, indicating that it hosts a companion with a long-period orbit. Subsequent imaging observations with the ShaneAO system on the Lick Observatory 3 m Shane telescope, the PHARO AO system on the Palomar Observatory 5 m telescope, and the NIRC2 AO system at the Keck II 10 m telescope reveal a faint companion 2.″7 from the primary star. We performed relative photometry, finding ΔJ = 10.09 ± 0.38 mag, {{Δ }}{K}_s=10.06+/- 0.22 mag, and {{Δ }}L^\prime =9.67+/- 0.08 mag for the companion from these observations. Analysis of the radial velocities, astrometry, and photometry reveals that the combined data set can only be reconciled for the scenario where HD 159062 B is a white dwarf. A full Bayesian analysis of the RV and imaging data to obtain the cooling age, mass, and orbital parameters of the white dwarf indicates that the companion is an old {M}_B={0.65}_-0.04^+0.12{M}_⊙ white dwarf with an orbital period of P={250}_-76⁺¹³⁰ yr, and a cooling age of τ ={8.2}_-0.5^+0.3 Gyr.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2019ApJ...878...50H
• PDF https://iopscience.iop.org/article/10.3847/1538-4357/ab1b11/pdf
• PDF https://stacks.iop.org/0004-637X/878/50/pdf
• PREPRINT http://arxiv.org/abs/1905.06440
• DATA https://irsa.ipac.caltech.edu/bibdata/2019/H/2019ApJ...878...50H.html
• ELECTR https://doi.org/10.3847%2F1538-4357%2Fab1b11