Multiwavelength Observations of the Runaway Binary HD 15137

• Published in: arXiv.org 2009-12
• Main Authors: McSwain, M Virginia, De Becker, Michael, Roberts, Mallory S E, Boyajian, Tabetha S, Gies, Douglas R, Grundstrom, Erika D, Aragona, Christina, Marsh, Amber N, Roettenbacher, Rachael M
• Format: Article
• Language: English
• Subjects: Binary stars; Companion stars; Deposition; Ejection; Emission spectra; Emissions control; Neutron stars; Neutrons; O stars; Physical properties; XMM (spacecraft)
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.0912.5133

HD 15137 is an intriguing runaway O-type binary system that offers a rare opportunity to explore the mechanism by which it was ejected from the open cluster of its birth. Here we present recent blue optical spectra of HD 15137 and derive a new orbital solution for the spectroscopic binary and physical parameters of the O star primary. We also present the first XMM-Newton observations of the system. Fits of the EPIC spectra indicate soft, thermal X-ray emission consistent with an isolated O star. Upper limits on the undetected hard X-ray emission place limits on the emission from a proposed compact companion in the system, and we rule out a quiescent neutron star in the propellor regime or a weakly accreting neutron star. An unevolved secondary companion is also not detected in our optical spectra of the binary, and it is difficult to conclude that a gravitational interaction could have ejected this runaway binary with a low mass optical star. HD 15137 may contain an elusive neutron star in the ejector regime or a quiescent black hole with conditions unfavorable for accretion at the time of our observations.