J/A+A/498/527ivo://CDS.VizieR/J/A+A/498/527doi:10.26093/cds/vizier.34980527CDSOnehag A.Gustafsson B.Eriksson K.Edvardsson B.2017-06-01T08:53:06Z2009-07-12T12:08:30ZCDS support team

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

cds-question@unistra.frastronomical-modelsstellar-atmospheresvisible-astronomymedium-band-photometrychemical-abundanceseffective-temperatureThe use of model atmospheres for deriving stellar fundamental parameters, such as Teff, log(g), and [Fe/H], will increase as we find and explore extreme stellar populations where empirical calibrations are not yet available. Moreover, calibrations for upcoming large satellite missions of new spectrophotometric indices, similar to the uvby-Hbeta system, will be needed. We aim to test the power of theoretical calibrations based on a new generation of MARCS models by comparisons with observational photometric data. We calculated synthetic uvby-Hbeta colour indices from synthetic spectra. A sample of 367 field stars, as well as stars in globular clusters, is used for a direct comparison of the synthetic indices versus empirical data and for scrutizing the possibilities of theoretical calibrations for temperature, metallicity, and gravity. We show that the temperature sensitivity of the synthetic (b-y) colour is very close to its empirical counterpart, whereas the temperature scale based upon Hbeta shows a slight offset. The theoretical metallicity sensitivity of the m1 index (and for G-type stars its combination with c1) is somewhat higher than the empirical one, based upon spectroscopic determinations. The gravity sensitivity of the synthetic c1 index shows satisfactory behaviour when compared to observations of F stars. For stars cooler than the sun, a deviation is significant in the c1-(b-y) diagram. The theoretical calibrations of (b-y), (v-y), and c1 seem to work well for Pop II stars and lead to effective temperatures for globular cluster stars supporting recent claims that atomic diffusion occurs in stars near the turnoff point of NGC 6397. Synthetic colours of stellar atmospheres can indeed be used, in many cases, to derive reliable fundamental stellar parameters. The deviations seen when compared to observational data could be due to incomplete linelists but are possibly also due to the effects of assuming plane-parallel or spherical geometry and LTE.2009A&A...498..527Ohttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/498/527CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/498/527https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/498/527http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/498/527https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/498/527https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/498/527http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/498/527GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/498/527/stellar (The comparison samples)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/498/527/stellar?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/498/527/stellar?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/498/527/stellar?GETtext/xml+votable180.050000true2.17041736.6272220.0055555555555555566/79 200 341 373 382 587 754 798 944 1297 1341 1556 1642 1749 1790 2678 2923 3005 3026 3138 3313 3390 3494 3712 3970 4373 4376 4574 5009 5154 5195 5230 5531 5569 5587 5614 5622 5670 5676 5853 6056 6058 6154 6166 6226 6256 6354 6539 6792 7075 7238 7334 7459 7560 7610 7710 8296 8476 8671 8767 8845 8873 8935 9083 9125 9327 9476 9537 9753 9831 9843 10055 10812 11177 11394 11412 11473 11534 12082 12424 12451 12464 12526 12544 12599 12604 12621 12694 12704 12962 13025 13028 13075 13114 13158 13282 13301 13494 13882 14298 14385 14419 14534 14630 14679 14690 14743 14881 15118 15170 15597 15621 15850 16069 16115 16213 16679 16759 16821 17136 17245 17486 17496 17564 17576 17578 17606 17730 17955 17989 18035 18123 18204 18425 18548 18821 18887 18978 18990 19179 19217 19237 19312 19347 19507 19816 20178 20390 20402 20446 20804 20835 21112 21269 21389 21550 21723 21901 22048 22118 22120 22205 22527 22654 22708 22818 23015 23070 23096 23533 23538 23540 23547 23623 23675 23695 23820 23974 23978 24048 24151 24752 24775 24827 24924 24942 25015 25051 25056 25444 25607 25846 25869 26158 26289 26302 26347 26521 26575 26975 27075 27857 27975 28136 28151 28336 28915 29021 29490 29703 29769 29958 30219 30227 30233 30296 30475 30518 30529 30577 30665 30798 30878 30939 30965 30974 31048 31172 31452 31478 31503 31751 31757 31760 31768 31874 32100 32619 32645 32684 32757 32889 33018 33131 33189 33273 33378 33456 33552 33580 33831 34088 34096 34171 34446 34864 35442 35994 36035 36114 36126 36221 36664 36697 36727 36745 36888 37232 37651 37831 37985 38072 38152 38216 38238 38255 38440 38566 38733 38908 38966 39030 39500 39679 39692 39709 39854 39893 40337 40567 40716 40722 40750 40885 40932 40944 41225 41460 41591 41721 41941 42331 42458 42555 42618 43062 43068 43280 43310 43445 43544 43641 43786 43797 43850 43962 44129 44208 44214 44281 44411 44501 44542 44653 44771 44816 44910 44931 45353 45485 45668 45843 46023 46053 46076 46626 46681 46909 47147 47347 47453 47589 47930 48226 48281 48394 48731 48736 49078 49106https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/498/527?format=asciiOpticaldefaultJ/A+A/498/527/stellarThe comparison samplesNameDesignationmeta.id;phys.atmol.configurationcharONameOther designationmeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainTeffEffective temperatureKphys.temperature.effectiveintloggLogaritmic surface gravitylog(cm.s**-2)phys.gravityfloat[Fe/H]? Metallicityphys.abund.Zfloatnullablec0Reddening corrected Stromgren c1 colour indexmagphot.color.reddFreefloatm0Reddening corrected Stromgren m1 colour indexmagphot.color.reddFreefloat(b-y)0Reddening corrected Stromgren (b-y) colour indexmagphot.color;em.opt.B;em.opt.VfloatHbeta? Stromgren H-beta indexmagphot.color;em.opt.B;em.line.HbetafloatnullableRefSource of reference from which photometric and/or fundamental parameters were gathered (1)meta.ref;pos.framecharSimbadSimbad column added by the CDScharJ/A+A/498/527/modelThe model coloursrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTeff[4500,7000] Effective temperatureKphys.temperature.effectiveintlogg[2.0,4.5] Logaritmic surface gravitylog(cm.s**-2)phys.gravityfloat[Fe/H][-5.0,0.5] Metallicityphys.abund.Zfloatc1Stromgren c1 colour indexmagphot.colorfloatm1Stromgren m1 colour indexmagphot.colorfloatb-yStromgren (b-y) colour indexmagphot.color;em.opt.B;em.opt.VfloatHbetaStromgren H-beta colour indexmagphot.color;em.opt.B;em.line.Hbetafloat