J/AJ/148/62ivo://CDS.VizieR/J/AJ/148/62doi:10.26093/cds/vizier.51480062CDSKoenigsberger G.Morrell N.Hillier D.J.Gamen R.Schneider F.R.N.,Gonzalez-Jimenez N.Langer N.Barba R.2017-07-05T06:59:39Z2014-11-26T14:48:30ZCDS support team

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

cds-question@unistra.frwolf-rayet-starseclipsing-binary-starsradial-velocityNew spectroscopic observations of the LBV/WR multiple system HD 5980 in the Small Magellanic Cloud are used to address the question of the masses and evolutionary status of the two very luminous stars in the 19.3 day eclipsing binary system. Two distinct components of the NV4944{AA} line are detected in emission and their radial velocity variations are used to derive masses of 61 and 66M_{sun}_, under the assumption that binary interaction effects on this atomic transition are negligible. We propose that this binary system is the product of quasi-chemically homogeneous evolution with little or no mass transfer. Thus, both of these binary stars may be candidates for gamma-ray burst progenitors or even pair instability supernovae. Analysis of the photospheric absorption lines belonging to the third-light object in the system confirm that it consists of an O-type star in a 96.56day eccentric orbit (e=0.82) around an unseen companion. The 5:1 period ratio and high eccentricities of the two binaries suggest that they may constitute a hierarchical quadruple system.2014AJ....148...62Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/148/62CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJ/745/173 : UV absorption sight lines of LMC and SMC (Welty+, 2012)J/AJ/143/28 : Analysis of B6-A9 stars from INES UV spectra (Freire+, 2012)J/ApJS/187/149 : StarCAT: STIS UV echelle spectra of stars (Ayres, 2010)J/PASP/121/634 : FUSE observations in Magellanic Clouds (Blair+, 2009)J/ApJS/144/21 : Galaxy and Magellanic Clouds OB and WR stars (Robert+, 2003)J/A+A/366/508 : S Dor variables (van Genderen+, 2001)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/148/62https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/148/62http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/148/62https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/148/62https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/148/62http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/148/62GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/148/62/spectraLas Campanas Observatory (LCO) spectrarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDispSimbad column added by the CDSmeta.id;instrcharYear[2006/2013] Year of observationyrtime.epochintTelTelescope (Baade Mag 1, Clay Mag 2, DuPont) (1)meta.id;instr.telcharInstInstrument (IMACS, MagE=Magellan Echellette)meta.id;instrcharHJDHeliocentric Julian Date (HJD-2450000)dtime.epochdoublePhase[0/1] Orbital phase (computed with P=19.26d)time.phasefloatJ/AJ/148/62/vel_CRadial velocity measurements for star CHJDHeliocentric Julian Date (HJD-2450000)dtime.epochdoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintInstSimbad column added by the CDSmeta.id;instrcharPhase1[0/1] Orbital phase computed with P=19.2654dtime.phasefloatPhase2[0/1] Orbital phase computed with P=96.56dtime.phasefloatRV5592[68/251]? Radial velocity obtained by fitting Gaussians to the core of the OIII{lambda}5592{AA} absorption linekm/sphys.veloc;pos.heliocentricintnullableu_RV5592[:] Uncertainty flag on RV5592meta.code.errorcharRV4471[69/268]? Radial velocity obtained by fitting Gaussians to the core of the HeI{lambda}4471{AA} absorption linekm/sphys.veloc;pos.heliocentricintnullableu_RV4471[:] Uncertainty flag on RV4471meta.code.errorcharRV5875[44/296]? Radial velocity obtained by fitting Gaussians to the core of the HeI{lambda}5875{AA} absorption linekm/sphys.veloc;pos.heliocentricintnullableRV5696[-14/256]? Radial velocity obtained by fitting Gaussians to the core of the CIII{lambda}5696{AA} emission linekm/sphys.veloc;pos.heliocentricintnullableu_RV5696[:] Uncertainty flag on RV5696meta.code.errorcharJ/AJ/148/62/table3Radial velocity measurements of NV 4944recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Date (HJD-2450000)dtime.epochdoublePhase[0/1] Orbital phase (computed with P=19.2654d)time.phasefloatRVA[-98/399]? Primary radial velocity (1)km/sphys.veloc;pos.heliocentricintnullableRVB[-142/344]? Secondary radial velocity (1)km/sphys.veloc;pos.heliocentricintnullable