J/ApJ/913/48ivo://CDS.VizieR/J/ApJ/913/48doi:10.26093/cds/vizier.19130048CDSGomez S.Grindlay J.E.2023-01-16T08:13:56Z2022-12-13T12:00:47ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frx-ray-binary-starsphotometryvisible-astronomyradial-velocityWe 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+/-0.00046days. 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 M_1_=22.7_-3.6_^+5.2^M_{sun}_ for the primary, and M_2_=6.2_-0.7_^+0.9^M_{sun}_ 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 {Gamma}=2.6 detected past 10keV 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.2021ApJ...913...48Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/913/48CatalogResearchIsServedByTAP VizieR generic servicerelated-toII/328 : AllWISE Data Release (Cutri+ 2013)VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)J/A+A/407/1039 : X-ray power spectra of Cygnus X-1 (Pottschmidt+, 2003)J/ApJ/681/562 : Orbits of 5 Cet and AX Mon (Eaton, 2008)J/A+A/480/611 : XMM-Newton slew survey catalogue, XMMSL1 (Saxton+, 2008)J/AN/331/349 : O, B & red supergiant masses & luminosities (Hohle+, 2010)J/ApJS/194/7 : X-ray properties of O and B stars in Carina (Naze+, 2011)J/ApJS/215/15 : SMaSH+: observations and companion detection (Sana+, 2014)J/A+A/613/A9 : Extinction towards Galactic O stars (Maiz Apellaniz+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/913/48https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/913/48http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/913/48https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/913/48https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/913/48http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/913/48GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapX-rayOpticaldefaultJ/ApJ/913/48/fig5aPhased V, B, R light curverecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Datedtime.epochdoublemag[7.47/7.76] Average V, B, R magnitudemagphot.mag;em.optfloate_mag[0.002/0.09] Uncertainty in magmagstat.error;phot.magfloatJ/ApJ/913/48/fig5bRadial velocity curverecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Datedtime.epochdoubleRVel[-86/33] Radial velocitykm/sphys.veloc;pos.heliocentricfloate_RVel[0.7/7] Uncertainty in RVelkm/sstat.error;spect.dopplerVelocfloat