J/A+A/690/A289ivo://CDS.VizieR/J/A+A/690/A289doi:10.26093/cds/vizier.36900289CDSShenar T.Bodensteiner J.Sana H.Crowther P.A.Lennon D.J.,Abdul-Masih M.Almeida L.A.Backs F.Berlanas S.R.Bernini-Peron M.,Bestenlehner J.M.Bowman D.M.Bronner V.A.Britavskiy N.de Koter A.,de Mink S.E.Deshmukh K.Evans C.J.Fabry M.Gieles M.Gilkis A.,Gonzalez-Tora G.Graefener G.Goetberg Y.Hawcroft C.Henault-Brunet V.,Herrero A.Holgado G.Janssens S.Johnston C.Josiek J.Justham S.,Kalari V.M.Katabi Z.Z.Keszthelyi Z.Klencki J.Kubat J.Kubatova B.,Langer N.Lefever R.R.Ludwig B.Mackey J.Mahy L.Maiz Apellaniz J.,Mandel I.Maravelias G.Marchant P.Menon A.Najarro F.Oskinova L.M.,O'Grady A.J.G.Ovadia R.Patrick L.R.Pauli D.Pawlak M.,Ramachandran V.Renzo M.Rocha D.F.Sander A.A.C.Sayada T.,Schneider F.R.N.Schootemeijer A.Schoesser E.C.Schuermann C.Sen K.,Shahaf S.Simon-Diaz S.Stoop M.Toonen S.Tramper F.van Loon J.T.,Valli R.van Son L.A.C.Vigna-Gomez A.Villasenor J.I.Vink J.S.,Wang C.Willcox R.2026-02-02T20:01:28Z2024-10-17T09:19:06ZCDS support team

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

cds-question@unistra.frmagellanic-cloudsstellar-populationsinfrared-photometrymorgan-keenan-classificationSurveys in the Milky Way and Large Magellanic Cloud have revealed that the majority of massive stars will interact with companions during their lives. However, knowledge of the binary properties of massive stars at low metallicity, and therefore in conditions approaching those of the Early Universe, remain sparse. We present the Binarity at LOw Metallicity (BLOeM) campaign, an ESO large programme designed to obtain 25 epochs of spectroscopy for 929 massive stars in the Small Magellanic Cloud, allowing us to probe multiplicity in the lowest-metallicity conditions to date (Z=0/2Z_{sun}_). BLOeM will provide (i) the binary fraction, (ii) the orbital configurations of systems with periods of P<~3yr, (iii) dormant black-hole binary candidates (OB+BH), and (iv) a legacy database of physical parameters of massive stars at low metallicity. Main sequence (OB-type) and evolved (OBAF-type) massive stars are observed with the LR02 setup of the giraffe instrument of the Very Large Telescope (3960-4570{AA} resolving power R=6200; typical signal-to-noise ratio (S/N)~70-100). This paper utilises the first nine epochs obtained over a three-month time period. We describe the survey and data reduction, perform a spectral classification of the stacked spectra, and construct a Hertzsprung-Russell diagram of the sample via spectral-type and photometric calibrations. Our detailed classification reveals that the sample covers spectral types from O4 to F5, spanning the effective temperature and luminosity ranges 6:5<~Te/kK<~45 and 3.7<logL/L_{sun}_<6.1 and initial masses of 8<~M_ini_<~80M_{sun}_. The sample comprises 159 O-type stars, 331 early B-type (B0-3) dwarfs and giants (luminosity classes V-III), 303 early B-type supergiants (II-I), and 136 late-type BAF supergiants. At least 82 stars are OBe stars: 20 O-type and 62 B-type (13% and 11% of the respective samples). In addition, the sample includes 4 high-mass X-ray binaries, 3 stars resembling luminous blue variables, 2 bloated stripped-star candidates, 2 candidate magnetic stars, and 74 eclipsing binaries.2024A&A...690A.289Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/690/A289CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/350 : Gaia EDR3 (Gaia Collaboration, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/690/A289https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/690/A289http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/690/A289https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/690/A289https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/690/A289http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/690/A289GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/690/A289/tablea2 (Aliases, K-band magnitudes, spectral types, and additional information for the 929 BLOeM targets)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/690/A289/tablea2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/690/A289/tablea2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/690/A289/tablea2?GETtext/xml+votable180.050000true11.77390938946-73.416418187350.0055555555555555566/33294-33295 33298 33304 33306 33317 333287.952274030004205e-20 1.0188844282367877e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/690/A289?format=asciiOpticalInfrareddefaultJ/A+A/690/A289/tablea2Aliases, K-band magnitudes, spectral types, and additional information for the 929 BLOeM targetsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDBLOeM identifier (N-NNN)meta.id;meta.maincharGaiaDR3Gaia Data Release 3 identifiermeta.idRA_ICRSGaia DR3 right ascension (ICRS) at Ep=2016.0degpos.eq.ra;meta.mainDE_ICRSGaia DR3 declination (ICRS) at Ep=2026.0degpos.eq.dec;meta.mainONameCommon aliases in the literaturemeta.notecharKsmag? K-band magnitudemagphot.mag;em.IR.KfloatnullableSpTypeoldLiterature spectral type (1)src.spTypecharSpTypenewSpectral type from this studysrc.spTypecharHalpha[yes no -] H-alpha emitters in Gaia low-resolution spectrameta.codecharCommentAdditional comments (1)meta.notecharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/A+A/690/A289/refsReferencesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference codemeta.notecharBibCodeBibCodemeta.bib.bibcodecharAutAuthor's namemeta.bib.authorcharComCommentsmeta.notechar