J/A+A/660/A89ivo://CDS.VizieR/J/A+A/660/A89doi:10.26093/cds/vizier.36600089CDSRitchie B.W.Clark J.S.Negueruela I.Najarro F.2024-12-10T20:00:51Z2022-09-28T13:14:12ZCDS support team

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

cds-question@unistra.fropen-star-clustersmultiple-starsradial-velocityvisible-astronomyThe galactic cluster Westerlund 1 contains a rich population of evolved, massive stars. A high binary fraction has been inferred from previous multi-wavelength observations. Aims. We use multi-epoch spectroscopy of a large sample of early-type stars in Westerlund 1 to identify new binaries and binary candidates in the cluster. VLT/FLAMES was used with the GIRAFFE spectrograph in HR21 mode to obtain spectra of ~100 OB stars over a 14-month baseline in 2008 and 2009, supplemented with follow-up observations in 2011 and 2013. Radial velocities were obtained from strong Paschen series absorption lines in the I-band. We identify 20 new OB I-III binaries, a WN9h binary, and a WC9d binary, greatly increasing the number of directly confirmed binary systems in Westerlund 1, while 12 O9-9.5 Iab-III stars are identified as candidate binaries based on radial velocity changes that are inconsistent with photospheric variability. The 173.9 day SB1 W1030 represents the first longer-period system identified in the cluster, while the determination of a 53.95 day period for W44 (WR L) makes it the first Wolf-Rayet binary in Westerlund 1 with a confirmed orbital period greater than ten days. Our results suggest the binary fraction in the OB population is at least ~40%, and may be significantly higher. These results demonstrate that binary systems can be effectively identified in the population of OB I-III stars evolving off the main sequence in Westerlund 1. Future multi-epoch surveys will be able to fully characterise this population.2022A&A...660A..89Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/660/A89CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/635/A187 : Massive binaries in Westerlund 1. VII. (Clark+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/660/A89https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/660/A89http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/660/A89https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/660/A89https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/660/A89http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/660/A89GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/660/A89/table5 (Binaries in Westerlund 1)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/660/A89/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/660/A89/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/660/A89/table5?GETtext/xml+votable180.050000true251.7488333-45.84755560.005555555555555556Cone search capability for table J/A+A/660/A89/table6 (Candidate binaries in Westerlund 1)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/660/A89/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/660/A89/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/660/A89/table6?GETtext/xml+votable180.050000true251.76725-45.84202780.005555555555555556Cone search capability for table J/A+A/660/A89/tablea1 (Summary of radial velocity observations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/660/A89/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/660/A89/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/660/A89/tablea1?GETtext/xml+votable180.050000true251.747-45.84630560.0055555555555555566/42206-42207https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/660/A89?format=asciiOpticaldefaultJ/A+A/660/A89/table5Binaries in Westerlund 1IDNamemeta.id;meta.maincharu_omega[?] Uncertainty flag on omega (3)meta.code.errorchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintONameOther namemeta.idcharn_IDNotes on ID (1)meta.notecharSpTypeSpectral typesrc.spTypecharSimbadNameSimbad column added by the CDSmeta.idcharnullableTypeType (2)src.classcharP? Perioddtime.periodfloatnullableu_P[? ] Uncertainty flag on P (3)meta.code.errorcharK1? K1 velocitykm/sphys.velocfloatnullableu_K1[?] Uncertainty flag on K1 (3)meta.code.errorcharK2? K2 velocitykm/sphys.velocfloatnullableu_K2[?] Uncertainty flag on K2 (3)meta.code.errorchargamma? Mass center of the system velocitykm/sphys.veloc;pos.barycenterfloatnullableu_gamma[?] Uncertainty flag on gamma (3)meta.code.errorcharl_e[~<>= ] Limit flag on emeta.code.errorchare? Eccentricitysrc.orbital.eccentricityfloatnullableu_e[?] Uncertainty flag on e (3)meta.code.errorcharl_omega[~] Limit flag on omegameta.code.errorcharomega? Perioastrondegsrc.orbital.periastronintnullableJ/A+A/660/A89/table6Candidate binaries in Westerlund 1_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDNamemeta.id;meta.maincharSpTypeSpectral type from Clark et al. (2020A&A...635A.187C, Cat. J/A+A/635/A187)src.spTypecharRVflag[o+-] Radial velocity changes flag (1)meta.codechar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.mainX-rayflag[o+-] X-ray luminosity flag from Clark et al., 2019A&A...626A..59C (1)meta.codecharIRflag[o+-] Infrared excess flag (1)meta.codecharr_IRflagReference for IRflag (2)meta.codecharradioflag[o+-] Non-thermal radio emission flag (1)meta.codecharr_radioflagReference for radioflag (2)meta.codecharMorphflagSpectral morphology flag (1)meta.codecharr_MorphflagReference for Morphflag (2)meta.codecharSimbadNameSimbad column added by the CDSmeta.idcharnullableJ/A+A/660/A89/tablea1Summary of radial velocity observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintONameOther namemeta.idcharn_IDNote on ID (1)meta.notecharSpTypeSpectral Typesrc.spTypecharNobsObservationsmeta.noteintP(null)? null probabilitystat.fit.goodnessfloatnullableRVmeanMean RV (1)km/sphys.veloc;stat.meanfloatRVrange? RV Rangekm/sinstr.bandwidthfloatnullablee_RVmeanMean error on RVkm/sstat.errorfloatsigmadet? Maximum significance of RV differences between any two epochs of observationstat.fit.goodnessfloatnullableT5[5]? 5 when sources in table5.dat (Binaries in Westerlund 1)meta.codeintnullableT6[6]? 6 when sources in table6.dat (Candidate binaries in Westerlund 1)meta.codeintnullable_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainSimbadNameSimbad column added by the CDSmeta.idcharnullableIDNamemeta.id;meta.mainchar