J/A+A/562/A75ivo://CDS.VizieR/J/A+A/562/A75doi:10.26093/cds/vizier.35620075CDSBritavskiy N.E.Bonanos A.Z.Mehner A.Garcia-Alvarez D.Prieto J.L.,Morrell N.I.2014-07-13T18:11:04Z2014-02-07T08:41:59ZCDS support team

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

cds-question@unistra.frgalaxiessupergiant-starslate-type-starsstellar-spectral-typesspectroscopyThe role of episodic mass loss in massive star evolution is one of the outstanding questions of current stellar evolution theory. Episodic mass loss produces dust and therefore causes evolved massive stars to be very luminous in the mid-infrared and dim at optical wavelengths. We aim to increase the number of investigated luminous mid-IR sources to shed light on the late stages of these objects. To achieve this we explore mid-IR selection criteria to identity dusty evolved massive stars in two nearby galaxies. The method is based on mid-IR colors, using 3.6um and 4.5um photometry from archival Spitzer Space Telescope images of nearby galaxies and J-band from 2MASS. We apply our criteria to two nearby star-forming dwarf-irregular galaxies: Sextans A and IC 1613, selecting 8 targets, which we follow up with spectroscopy. Our spectral classification and analysis yielded the discovery of 2 M-type supergiants in IC 1613, 3 K-type supergiants and 1 candidate F-type giant in Sextans A, and 2 foreground M giants. We show that the proposed criteria provide an independent way for identifying dusty evolved massive stars, which can be extended to all nearby galaxies with available Spitzer/IRAC images at 3.6um and 4.5um.2014A&A...562A..75Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/562/A75CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/562/A75https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/562/A75http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/562/A75https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/562/A75https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/562/A75http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/562/A75GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/562/A75/stars (Characteristics of the program stars, log of observations, radial velocities, CaT* indices and spectral types)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/562/A75/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/562/A75/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/562/A75/stars?GETtext/xml+votable180.050000true152.74217083-4.702470.0055555555555555566/18041 268583.322582951404819e-19 3.852589004194616e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/562/A75?format=asciiOpticaldefaultJ/A+A/562/A75/starsCharacteristics of the program stars, log of observations, radial velocities, CaT* indices and spectral typese_RVrms uncertainty on RVkm/sstat.errorintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarStar Namemeta.id;meta.maincharDateUT Date (HJD-2450000)dtime.epochdoubleTexpExposure timestime.duration;obs.exposureintSNRSignal-to-noise ratiostat.snrintRVRadial velocity (4)km/sphys.veloc;pos.heliocentricintCaT*Calcium triplet index (defined by Cenarro et al., 2001MNRAS.326..959C)spect.indexfloate_CaT*rms uncertainty on CaT*stat.errorfloatSpTypeSpectral temperature class (F, early K, late K, M0-2, M2-4, or late M)src.spTypecharSpLumLuminosity classificationphys.luminositycharFileNameName of FITS file with spectrum in subdirectory "sp"meta.id;meta.fitscharspPlot the spectrum ({lambda}=0.4--1.0{mu}m)meta.ref.urlcharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainVmag? V magnitudemagphot.mag;em.opt.Vfloatnullablee_Vmag? rms uncertainty on Vmagmagstat.error;phot.mag;em.opt.Vfloatnullablen_Vmag[*] Several magnitude measurements (1)meta.notecharB-V? B-V colour indexmagphot.color;em.opt.B;em.opt.Vfloatnullablee_B-V? rms uncertainty on B-Vmagstat.error;phot.color;em.opt.BfloatnullableV-R? V-R colour indexmagphot.color;em.opt.V;em.opt.Rfloatnullablee_V-R? rms uncertainty on V-Rmagstat.error;phot.color;em.opt.VfloatnullableM3.6Absolute 3.6um magnitude (2)magphys.magAbs;em.IR.3-4umfloat[3.6/4.5]IRAC [3.6]-[4.5] colour indexmagphot.color;em.IR;em.IRfloatJ-[3.6]J-[3.6] colour indexmagphot.color;em.IR;em.IRfloate_J-[3.6]rms uncertainty on J-[3.6]magstat.errorfloatJ-HJ-H colour indexmagphot.color;em.IR.J;em.IR.Hfloate_J-Hrms uncertainty on J-Hmagstat.error;phot.color;em.IR.JfloatH-KH-K colour indexmagphot.color;em.IR.H;em.IR.Kfloate_H-Krms uncertainty on H-Kmagstat.error;phot.color;em.IR.HfloatQ1Near-IR index Q1 (3)stat.stdevfloatQ2? Near-IR index Q2 (3)stat.stdevfloatnullable