J/A+A/575/A12ivo://CDS.VizieR/J/A+A/575/A12doi:10.26093/cds/vizier.35750012CDSValle G.Dell'Omodarme M.Prada Moroni P.G.Degl'Innocenti S.2017-06-19T07:57:22Z2015-07-29T15:00:23ZCDS support team

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

cds-question@unistra.frstellar-massesstellar-agesastronomical-modelsStellar age determination by means of grid-based techniques that adopt asteroseismic constraints is a well established method nowadays. However some theoretical aspects of the systematic and statistical errors affecting these age estimates still have to be investigated. We study the impact on stellar age determination of the uncertainty in the radiative opacity, in the initial helium abundance, in the mixing-length value, in the convective core overshooting, and in the microscopic diffusion efficiency adopted in stellar model computations. We extended our SCEPtER grid to include stars with mass in the range [0.8; 1.6]M_{sun}_ and evolutionary stages from the zero-age main sequence to the central hydrogen depletion. For the age estimation we adopted the same maximum likelihood technique as described in our previous work. To quantify the systematic errors arising from the current uncertainty in model computations, many synthetic grids of stellar models with perturbed input were adopted. We found that the current typical uncertainty in the observations accounts for 1{sigma} statistical relative error in age determination, which on average ranges from about -35% to +42%, depending on the mass. However, owing to the strong dependence on the evolutionary phase, the age's relative error can be higher than 120% for stars near the zero-age main sequence, while it is typically of the order of 20% or lower in the advanced main-sequence phase. The systematic bias on age determination due to a variation of +/-1 in the helium-to-metal enrichment ratio {Delta}Y/{Delta}Z is about one-fourth of the statistical error in the first 30% of the evolution, while it is negligible for more evolved stages. The maximum bias due to the presence of the convective core overshooting is -7% and -13% for mild and strong overshooting scenarios. For all the examined models, the impact of a variation of +/-5% in the radiative opacity was found to be negligible. The most important source of bias is the uncertainty in the mixing-length value {alpha}_ml_ and the neglect of microscopic diffusion. Each of these effects accounts for a bias that is nearly equal to the random error uncertainty. Comparison of the results of our technique with other grid techniques on a set of common stars showed general agreement. However, the adoption of a different grid can account for a variation in the mean estimated age up to 1Gyr.2015A&A...575A..12Vhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/575/A12CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toV/133 : Kepler Input Catalog (Kepler Mission Team, 2009)J/ApJ/749/152 : Asteroseismic analysis of 22 solar-type stars (Mathur+, 2012)J/ApJS/210/1 : Asteroseismic study of solar-type stars (Chaplin+, 2014)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/575/A12https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/575/A12http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/575/A12https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/575/A12https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/575/A12http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/575/A12GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/575/A12/stars (SCEPtER unweighted age and mass estimates for the samples of Mathur et al. 2012 (J/ApJ/749/152) and Chaplin et al. 2014 (J/ApJS/210/1))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/575/A12/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/575/A12/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/575/A12/stars?GETtext/xml+votable180.050000true287.361813938.71401640.0055555555555555566/14573 14578 14581 14591 14734 14751 14754 14757 14763 14767 14770-14771 14774 14776 14779 14794 14819 14824 14918 14921-14922 14926 14930-14933 14935 14938-14939 14941 14947-14948 14959-14961 14966-14967 14969 15044 15057 15061-15062 15104-15106 15108 15112 15118 15121 15124 15126 15131-15132 15141 15145-15146 15156 15168 15178https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/575/A12?format=asciidefaultJ/A+A/575/A12/starsSCEPtER unweighted age and mass estimates for the samples of Mathur et al. 2012 (J/ApJ/749/152) and Chaplin et al. 2014 (J/ApJS/210/1)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTSimbad column added by the CDSmeta.id;meta.datasetcharKICStar KIC number (V/133)meta.id;meta.mainintn_KICSimbad column added by the CDSmeta.ref.urlintnullableAge[0.9/14.5] AgeGyrtime.agefloatE_Age[0/2.6] Error in Age (upper value)Gyrstat.error;stat.maxfloate_Age[0/2.6] Error in Age (lower value)Gyrstat.error;time.agefloatMass[0.8/1.6] MasssolMassphys.massfloatE_Mass[0/0.2] Error in Mass (upper value)solMassstat.error;stat.maxfloate_Mass[0/0.2] Error in Mass (lower value)solMassstat.error;phys.massfloatMDetails from the original papermeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar_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.main