Discovery of a White Dwarf Companion to HD 159062
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, ΔK_S = 10.06±0.22 mag, and ΔL′ = 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^(+0.12)_(−0.04) M_⊙ white dwarf with an orbital period of P = 250^(+130)_(−76) yr, and a cooling age of τ = 8.2^(+0.3)_(−0.5) Gyr.
Additional Information
© 2019 The American Astronomical Society. Received 2018 October 1; revised 2019 April 16; accepted 2019 April 17; published 2019 June 12. We would like to thank the anonymous referee for many helpful and detailed suggestions that have helped to improve this manuscript. We thank Pierre Bergeron for providing updated white dwarf cooling models including L'-band synthetic photometry. L.A.H. would like to thank James Graham for helpful discussion on this project, and Erik Petigura for carrying out HIRES observations and performing a spectroscopic analysis of the properties of HD 159062 A. M.R.K acknowledges support from the NSF Graduate Research Fellowship, grant No. DGE 1339067. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. 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: Keck:I (HIRES) - , Keck:II (NIRC2) - , Lick:Shane (ShARCS) - , Palomar:Hale (PHARO). - Software: Emcee (Foreman-Mackey et al. 2013), VIP (Gomez Gonzalez et al. 2017), isoclassify (Huber et al. 2017), pyKLIP (Wang et al. 2015), photutils (Bradley et al. 2017).Attached Files
Published - Hirsch_2019_ApJ_878_50.pdf
Submitted - 1905.06440.pdf
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Additional details
- Eprint ID
- 96390
- Resolver ID
- CaltechAUTHORS:20190613-114026491
- DGE-1339067
- NSF Graduate Research Fellowship
- W. M. Keck Foundation
- Created
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2019-06-13Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Astronomy Department