J/ApJ/748/96ivo://CDS.VizieR/J/ApJ/748/96doi:10.26093/cds/vizier.17480096CDSMassey P.Morrell N.I.Neugent K.F.Penny L.R.DeGioia-Eastwood K.,Gies D.R.2017-06-21T08:21:42Z2013-11-18T09:06:40ZCDS support team

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

cds-question@unistra.frvariable-starseclipsing-binary-starso-starsradial-velocityphotometrystellar-spectral-typesThe stellar mass-luminosity relation is poorly constrained by observations for high-mass stars. We describe our program to find eclipsing massive binaries in the Magellanic Clouds using photometry of regions rich in massive stars, and our spectroscopic follow-up to obtain radial velocities and orbits. Our photometric campaign identified 48 early-type periodic variables, of which only 15 (31%) were found as part of the microlensing surveys. Spectroscopy is now complete for 17 of these systems, and in this paper we present analysis of the first two, LMC 172231 and ST2-28, simple detached systems of late-type O dwarfs of relatively modest masses. Our orbit analysis yields very precise masses (~2%), and we use tomography to separate the components and determine effective temperatures by model fitting, necessary for determining accurate (0.05-0.07 dex) bolometric luminosities in combination with the light-curve analysis. Our approach allows more precise comparisons with evolutionary theory than previously possible. To our considerable surprise, we find a small, but significant, systematic discrepancy: all of the stars are slightly undermassive, by typically 11% (or overluminous by 0.2 dex) compared with that predicted by the evolutionary models. We examine our approach for systematic problems, but find no satisfactory explanation. The discrepancy is in the same sense as the long-discussed and elusive discrepancy between the masses measured from stellar atmosphere analysis with the stellar evolutionary models, and might suggest that either increased rotation or convective overshooting is needed in the models.2012ApJ...748...96Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/748/96CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AcA/62/247 : OGLE-III shallow survey LMC photometric maps (Ulaczyk+, 2012)J/AcA/61/103 : VI light curves of LMC eclipsing binaries (Szymanski+, 2011)J/AJ/138/1003 : IR photometry of massive LMC stars (Bonanos+, 2009)J/AJ/134/1963 : MACHO light curves of MC eclipsing binaries (Faccioli+, 2007)J/ApJ/663/249 : LMC eclipsing binaries in the MACHO database (Derekas+, 2007)J/AJ/130/2701 : Stars in the Sagittarius Rift (Fresneau+, 2005)J/AcA/54/1 : OGLE II SMC eclipsing binaries (Wyrzykowski+, 2004)J/AJ/128/1606 : Magellanic Clouds Photometric Survey: the LMC (Zaritsky+, 2004)J/AJ/119/2214 : Photometry of Magellanic OB associations (Massey+, 2000)J/AJ/114/326 : MACHO Variables V. (Alcock+ 1997)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/748/96https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/748/96http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/748/96https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/748/96https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/748/96http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/748/96GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/748/96/table3 (Identified periodic variables in SMC and LMC)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/748/96/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/748/96/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/748/96/table3?GETtext/xml+votable180.050000true14.618375-72.20952780.0055555555555555566/33094 33099 33317 33328https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/748/96?format=asciiOpticaldefaultJ/ApJ/748/96/table6Radial velocities of LMC 172231PhasePhase (1)time.phasefloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Datedtime.epochdoubleV1[15.6/523.7] Primary radial velocitykm/sspect.dopplerVelocfloate_V1[0.2/10]? V1 standard deviation of the meankm/sstat.errorfloatnullableV2[-23.2/571.7] Secondary radial velocitykm/sspect.dopplerVelocfloate_V2[1.9/13.6]? V2 standard deviation of the meankm/sstat.errorfloatnullableN[1/17] Number of spectral lines usedmeta.numberintJ/ApJ/748/96/table9ST2-28 photometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Daydtime.epoch;pos.heliocentricdoubleVmag[13.993/14.613] The V band magnitudemagphot.mag;em.opt.Vfloate_Vmag[0.003/0.032] Error in Vmagmagstat.error;phot.mag;em.opt.VfloatIndex[1/3] Telescope/Instrument Combination (1)meta.codeintPhaseOrbital phase (2)time.phasefloatJ/ApJ/748/96/table10Radial velocities of ST2-28 (He II lines only)PhasePhase (1)time.phasefloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Datedtime.epochdoubleV1[15.6/523.7] Primary radial velocitykm/sspect.dopplerVelocfloate_V1[0.2/10]? V1 standard deviation of the meankm/sstat.errorfloatnullableV2[-23.2/571.7] Secondary radial velocitykm/sspect.dopplerVelocfloate_V2[1.9/13.6]? V2 standard deviation of the meankm/sstat.errorfloatnullableN[1/17] Number of spectral lines usedmeta.numberintJ/ApJ/748/96/table3Identified periodic variables in SMC and LMCSimbadNameSimbad column added by the CDSmeta.idcharRegRegionmeta.id.parentcharONameOther namemeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.maincharRefReference(s) (1)meta.ref;pos.framecharRAJ2000[0/5] Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000[69/72] Degree of declination (J2000)pos.eq.dec;meta.mainSpTMK spectral typesrc.spTypecharr_SpT[ce] Reference flag for SpT (2)meta.ref;pos.framecharPer[1.062/8.105] Perioddtime.perioddoubleStatusStudy statusmeta.notecharPer2[1.360,8.099]? Period from litteraturedtime.perioddoublenullabler_Per2[,bdf-l] Flag(s) for Per2 or Name (2)meta.ref;pos.framecharLCPlot the light curves for LMC 172231 and ST2-28meta.ref.urlcharJ/ApJ/748/96/table5LMC 172231 photometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Daydtime.epoch;pos.heliocentricdoubleVmag[13.993/14.613] The V band magnitudemagphot.mag;em.opt.Vfloate_Vmag[0.003/0.032] Error in Vmagmagstat.error;phot.mag;em.opt.VfloatIndex[1/3] Telescope/Instrument Combination (1)meta.codeintPhaseOrbital phase (2)time.phasefloat