J/A+A/556/A121ivo://CDS.VizieR/J/A+A/556/A121doi:10.26093/cds/vizier.35560121CDSGiridhar S.Goswami A.Kunder A.Muneer S.Selvakumar G.2017-09-22T16:15:34Z2014-01-09T15:38:34ZCDS support team

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

cds-question@unistra.frg-starsmetallicityeffective-temperatureIdentification of metal-poor stars among field stars is extremely useful for studying the structure and evolution of the Galaxy and of external galaxies. We search for metal-poor stars using the artificial neural network (ANN) and extend its usage to determine absolute magnitudes. We have constructed a library of 167 medium-resolution stellar spectra (R~1200) covering the stellar temperature range of 4200 to 8000K, logg range of 0.5 to 5.0, and [Fe/H] range of -3.0 to dex. This empirical spectral library was used to train ANNs, yielding an accuracy of 0.3dex in [Fe/H], 200K in temperature, and 0.3dex in logg. We found that the independent calibrations of near-solar metallicity stars and metal-poor stars decreases the errors in Teff and logg by nearly a factor of two.2013A&A...556A.121Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/556/A121CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/556/A121https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/556/A121http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/556/A121https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/556/A121https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/556/A121http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/556/A121GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/556/A121/table1 (List of observed stars and their parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/556/A121/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/556/A121/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/556/A121/table1?GETtext/xml+votable180.050000true2.0145283-33.52932560.005555555555555556Cone search capability for table J/A+A/556/A121/table2 (Estimated atmospheric parameters for candidate metal-poor stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/556/A121/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/556/A121/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/556/A121/table2?GETtext/xml+votable180.050000true6/350 798 1415 1460 2006 3138 3164 3362 3377 4156 4181 4227 4338 4376 4423 4438 4469 4559 4847 5095 5154 5166 5180 5375 5535 5658 6015 6058 6166 6219 6255 6339 6504 6634 6739 7074 7142 7171 7198 7238 7352 7444 7710 7794 7992 8154 8336 8827 8845 8887 9127 9191 10899 10980 11274 16069 16436 16818 17363 20493 20518 20617 20659 20998 21014 21025 21089 21112 21269 21352 21485 21864 22071 22328 22655 22662 22822 22900 22932 23190 23266 23403 23479 23656 23722 23978 24048 24240 24271 24333 24553 24634 24771 24877 24885 24936 24964 25028 25074 25092 25110 25182 25246 25267 25269 25733 25891 25966 26109 26155 26172 26292 26347 26457 26528 26552 26651 26675 26687 26690 27040 27191 27235 27248 27380 27448 27763 27777 28005 28154 28257 28336 28338 28389 28393 28480 28483 28605 28664 29548 30529 30965 30974 31319 31408 31416 31576 31757 31784 32034 32352 32645 33788 33923 34749 35459 35602 35865 36008 36329 37358 38250 38339 38378 38391 38393 38860 38922 38967 39009 39047 39407 39647 39702 39893 40046 40213 40222 40337 40405 40408 40414 40519 40580 40716 41784 41887 43223 43275 43338 43608 43613 43763 43955 44281 44590 44675-44676 44701 44720-44721 44816 44869 44899 487983.322582951404819e-19 3.852589004194616e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/556/A121?format=asciiOpticaldefaultJ/A+A/556/A121/table1List of observed stars and their parametersSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeqSequential numbermeta.recordintNameStar namemeta.id;meta.maincharn_Name[*] indicates a star with known metallicitymeta.notecharHIP? Hipparcos identification number (I/311)meta.idintnullableVmag? V magnitudemagphot.mag;em.opt.VfloatnullableB-V? B-V colour indexmagphot.color;em.opt.B;em.opt.VfloatnullablelogglLiterature surface gravitylog(cm.s**-2)phys.gravityfloatTefflLiterature effective temperatureKphys.temperature.effectivefloat[Fe/H]l? Literature metallicitylog(Sun)phys.abund.Fefloatnullabler_[Fe/H]l? Reference for [Fe/H]l, in refs.dat filemeta.ref;pos.frameintnullableVMAGl? Literature absolute V magnitudemagphys.magAbsfloatnullableloggArtificial neural network surface gravitylog(cm.s**-2)phys.gravityfloatTeffArtificial neural network effective temperatureKphys.temperature.effectivefloat[Fe/H]? Artificial neural network metallicitylog(Sun)phys.abund.ZfloatnullableVMAG? Artificial neural network absolute V magnitudemagphys.magAbs;em.opt.Vfloatnullable_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.mainJ/A+A/556/A121/table2Estimated atmospheric parameters for candidate metal-poor starsSimbadNameSimbad column added by the CDSmeta.idcharNameStar namemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintm_Name[abc] Spectrum number when more than one for the star (1)meta.code.multipcharloggArtificial neural network surface gravitylog(cm.s**-2)phys.gravityfloat[Fe/H]Artificial neural network metallicitylog(Sun)phys.abund.ZfloatTeffArtificial neural network effective temperatureKphys.temperature.effectivefloatB-V? B-V colour indexmagphot.color;em.opt.B;em.opt.VfloatnullableDTeff? Effective temperature difference, Teff(ANN)-Teff(B-V)Kphys.temperaturefloatnullableVMAGAbsolute V magnitudemagphys.magAbs;em.opt.Vfloatu_VMAG[*] Uncertainty flag on VMAG (2)meta.code.errorchar_RASimbad column added by the CDSdegpos.eq.ra;meta.mainnullable_DESimbad column added by the CDSdegpos.eq.dec;meta.mainnullableJ/A+A/556/A121/refsReferencesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference numbermeta.id;meta.mainintBibCodeBibCodemeta.bib.bibcodecharAutAuthor's namemeta.bib.authorcharComCommentsmeta.notechar