J/A+A/658/A69ivo://CDS.VizieR/J/A+A/658/A69doi:10.26093/cds/vizier.36580069CDSBanyard G.Sana H.Mahy L.Bodensteiner J.Villasenor J.I.Evans C.J.2023-11-03T12:20:56Z2022-02-03T08:01:56ZCDS support team

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

cds-question@unistra.fropen-star-clustersradial-velocityb-starsvisible-astronomyIt is well known that massive O stars are frequently (if not always) found in binary or higher-order multiple systems, but this fact has been less robustly investigated for the lower mass range of the massive stars, represented by B-type stars. Obtaining the binary fraction and orbital parameter distributions of B-type stars is crucial to understand the impact of multiplicity on the archetypal progenitor of core-collapse supernovae as well as to properly investigate formation channels for gravitational wave progenitors. This work aims to characterise the multiplicity of the B star population of the young open cluster NGC 6231 through multi-epoch optical spectroscopy of 80 B-type stars. We analyse 31 FLAMES/GIRAFFE observations of 80 B-type stars, monitoring their radial velocities (RVs) and performing a least-squares spectral analysis (Lomb-Scargle) to search for periodicity in those stars with statistically significant variability in their RVs. We constrained an observed spectroscopic binary fraction of 33+/-5% for the B-type stars of NGC 6231, with a first order bias correction giving a true spectroscopic binary fraction of 52+/-8%. Out of 27 B-type binary candidates, we obtained orbital solutions for 20 systems: 15 single-lined (SB1) and five double-lined spectroscopic binaries (SB2s). We present these orbital solutions and the orbital parameter distributions associated with them. Our results indicate that Galactic B-type stars are less frequently found in binary systems than their more massive O-type counterparts, but their orbital properties generally resemble those of B- and O-type stars in both the Galaxy and Large Magellanic Cloud.2022A&A...658A..69Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/658/A69CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/386/447 : RV catalogue of O-type stars in NGC 6231 (Sana+, 2008)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/658/A69https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/658/A69http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/658/A69https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/658/A69https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/658/A69http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/658/A69GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/658/A69/stars (List of studied stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/658/A69/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/658/A69/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/658/A69/stars?GETtext/xml+votable180.050000true253.5211667-41.835250.0055555555555555566/42394https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/658/A69?format=asciiOpticaldefaultJ/A+A/658/A69/starsList of studied starsObjectObject name in SIMBADmeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSimbadSimbad column added by the CDSmeta.ref.urlcharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainFileNameName of the table with RV datameta.id;meta.tablecharVCShow the Radial Velocity curvesmeta.ref.urlcharJ/A+A/658/A69/sb2RVs of identified SB2s (5 stars) (table C1)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObjectObject name in SIMBADmeta.id;meta.maincharm_Object[1/2] For SB2, 1 for primary, 2 for secondarymeta.code.multipcharBJDBaricentric Julian date (BJD-2400000)dtime.epochdoubleRV? Radial velocity at BJDkm/sphys.veloc;pos.heliocentricdoublenullablee_RV? Error on RV at BJDkm/sstat.errorfloatnullableJ/A+A/658/A69/sb1RVs of identified SB1s (15 stars) (table C2)ObjectObject name in SIMBADmeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintm_Object[1/2] For SB2, 1 for primary, 2 for secondarymeta.code.multipcharBJDBaricentric Julian date (BJD-2400000)dtime.epochdoubleRV? Radial velocity at BJDkm/sphys.veloc;pos.heliocentricdoublenullablee_RV? Error on RV at BJDkm/sstat.errorfloatnullableJ/A+A/658/A69/varnopRVs of RV variable stars without an identified period (41 stars) (table C4)m_Object[1/2] For SB2, 1 for primary, 2 for secondarymeta.code.multipcharBJDBaricentric Julian date (BJD-2400000)dtime.epochdoubleRV? Radial velocity at BJDkm/sphys.veloc;pos.heliocentricdoublenullablee_RV? Error on RV at BJDkm/sstat.errorfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObjectObject name in SIMBADmeta.id;meta.maincharJ/A+A/658/A69/nonvarRVs of stars identified as stable in RV (12 stars) (table C5)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObjectObject name in SIMBADmeta.id;meta.maincharm_Object[1/2] For SB2, 1 for primary, 2 for secondarymeta.code.multipcharBJDBaricentric Julian date (BJD-2400000)dtime.epochdoubleRV? Radial velocity at BJDkm/sphys.veloc;pos.heliocentricdoublenullablee_RV? Error on RV at BJDkm/sstat.errorfloatnullableJ/A+A/658/A69/pnororbRVs of RV variable stars with an identified period but no constrained orbital solution (7 stars) (table C3)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObjectObject name in SIMBADmeta.id;meta.maincharm_Object[1/2] For SB2, 1 for primary, 2 for secondarymeta.code.multipcharBJDBaricentric Julian date (BJD-2400000)dtime.epochdoubleRV? Radial velocity at BJDkm/sphys.veloc;pos.heliocentricdoublenullablee_RV? Error on RV at BJDkm/sstat.errorfloatnullable