2021ApJ...913...48G -
Astrophys. J., 913, 48-48 (2021/May-3)
Optical analysis and modeling of HD96670, a new black hole X-ray binary candidate.
GOMEZ S. and GRINDLAY J.E.
Abstract (from CDS):
We report on optical observations and modeling of HD96670, a single-line spectroscopic binary in the Carina OB2 association. We collected 10 epochs of optical spectroscopy, and optical photometry on 17 nonconsecutive nights on the source. We construct a radial velocity curve from the spectra, and update the orbital period of the binary to be P = 5.28388 ± 0.00046 days. The spectra show oxygen and helium absorption, consistent with an O-type primary. We see no evidence for spectral lines from the secondary star in the binary. We model the optical light curve and radial velocity curve simultaneously using the Wilson-Devinney code and find a best-fit mass of M1=22.7–3.6+5.2M☉ for the primary, and M2=6.2–0.7+0.9M☉ for the secondary. An object of this mass is consistent with either a B-type star, or a black hole. Given that we see no absorption lines from the secondary, in combination with an observed hard power-law X-ray spectrum with Γ = 2.6 detected past 10 keV that may have been produced by wind accretion onto the secondary, we conclude that the secondary is most likely a black hole. We see asymmetrical helium lines with a shape consistent with the presence of a third star. If the secondary is indeed a black hole, this system would add to the small sample of only four possible black hole high mass X-ray binaries in the galaxy.
Abstract Copyright:
© 2021. The American Astronomical Society. All rights reserved.
Journal keyword(s):
High mass x-ray binary stars - X-ray binary stars
VizieR on-line data:
<Available at CDS (J/ApJ/913/48): fig5a.dat fig5b.dat>
Simbad objects:
7
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