J/A+A/558/A103ivo://CDS.VizieR/J/A+A/558/A103doi:10.26093/cds/vizier.35580103CDSGeorgy C.Ekstrom S.Eggenberger P.Meynet G.Haemmerle L.,Maeder A.Granada A.Groh J.H.Hirschi R.Mowlavi N.,Yusof N.Charbonnel C.Decressin T.Barblan F.2014-04-13T15:20:32Z2013-10-14T09:18:57ZCDS support team

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

cds-question@unistra.frstellar-evolutionary-modelsstellar-mass-losssupergiant-starsmagellanic-cloudsWe study the impact of a subsolar metallicity on various properties of non-rotating and rotating stars, such as surface velocities and abundances, lifetimes, evolutionary tracks, and evolutionary scenarios. We provide a grid of single star models covering a mass range of 0.8 to 120M_{sun_} with an initial metallicity Z=0.002 with and without rotation. We discuss the impact of a change in the metallicity by comparing the current tracks with models computed with exactly the same physical ingredients but with a metallicity Z=0.014 (solar). We show that the width of the main-sequence (MS) band in the upper part of the Hertzsprung-Russell diagram (HRD), for luminosity above log(L/L_{sun}_)>5.5, is very sensitive to rotational mixing. Strong mixing significantly reduces the MS width. Here for the first time over the whole mass range, we confirm that surface enrichments are stronger at low metallicity provided that comparisons are made for equivalent initial mass, rotation, and evolutionary stage. We show that the enhancement factor due to a lowering of the metallicity (all other factors kept constant) increases when the initial mass decreases. Present models predict an upper luminosity for the red supergiants (RSG) of log (L/L_{sun}_) around 5.5 at Z=0.002 in agreement with the observed upper limit of RSG in the Small Magellanic Cloud. We show that models using shear diffusion coefficient, which is calibrated to reproduce the surface enrichments observed for MS B-type stars at Z=0.014, can also reproduce the stronger enrichments observed at low metallicity. In the framework of the present models, we discuss the factors governing the timescale of the first crossing of the Hertzsprung gap after the MS phase. We show that any process favouring a deep localisation of the H-burning shell (steep gradient at the border of the H-burning convective core, low CNO content), and/or the low opacity of the H-rich envelope favour a blue position in the HRD for the whole, or at least a significant fraction, of the core He-burning phase.2013A&A...558A.103Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/558/A103CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/537/A146 : Stellar models with rotation. 0.8<M<120, Z=0.014, Paper I.J/A+A/543/A108 : Grid of stellar models, asteroseismology (Lagarde+, 2012)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/558/A103https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/558/A103http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/558/A103https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/558/A103https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/558/A103http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/558/A103GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/558/A103/tablesEvolutionary tracksYc4He central abundance (mass fraction)phys.abund;em.wl.centralfloatveqEquatorial velocitykm/sphys.veloc.rotatdoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMini[0.8/120] Initial masssolMassphys.massfloattrackEvolutionary track for this massmeta.ref.urlcharZini[0.002] Initial metallicityphys.abund.ZfloatRot[nr] r for rotation, n for no rotationmeta.codecharLine[1/400] Number of selected pointmeta.idintTimeAgeyrtime.agedoubleMassActual masssolMassphys.massdoublelogLLuminosity in log scalelog(solLum)phys.luminosityfloatlogTeEffective temperature in log scalelog(K)phys.temperature.effective;instr.scalefloatXH surface abundance (mass fraction)phys.abund.FefloatYHe surface abundance (mass fraction)phys.abund.YfloatC1212C surface abundance (mass fraction)meta.notedoubleC1313C surface abundance (mass fraction)meta.notedoubleN1414N surface abundance (mass fraction)meta.notedoubleO1616O surface abundance (mass fraction)meta.notedoubleO1717O surface abundance (mass fraction)meta.notedoubleO1818O surface abundance (mass fraction)meta.notedoubleNe2020Ne surface abundance (mass fraction)meta.notedoubleNe2222Ne surface abundance (mass fraction)meta.notedoubleAl2626Al surface abundance (mass fraction)phys.abunddoubleQCCConvective core mass fractionphys.massfloatlogTe.uUncorrected effective temperature in log scale (WR stars only)log(K)phys.temperature.effectivefloatlogdM/dtMass loss rate in log scalelog(solMass.yr**-1)phys.mass.lossdoublelog(rhoc)Central density in log scalelog(g.cm**-3)instr.scalefloatlogTcCentral temperature in log scalelog(K)instr.scalefloatXcH central abundance (mass fraction)phys.abund.FefloatC12c12C central abundance (mass fraction)phys.abund;em.wl.centraldoubleC13c13C central abundance (mass fraction)phys.abund;em.wl.centraldoubleN14c14N central abundance (mass fraction)phys.abund;em.wl.centraldoubleO16c16O central abundance (mass fraction)phys.abund;em.wl.centraldoubleO17c17O central abundance (mass fraction)phys.abund;em.wl.centraldoubleO18c18O central abundance (mass fraction)phys.abund;em.wl.centraldoubleNe20c20Ne central abundance (mass fraction)phys.abund;em.wl.centraldoubleNe22c22Ne central abundance (mass fraction)phys.abund;em.wl.centraldoubleAl26c26Al central abundance (mass fraction)phys.abunddoubleOmegasSurface angular velocity {Omega}srad/sphys.veloc.angdoubleOmegacCentral angular velocity {Omega}crad/sphys.veloc.angdoubleoblat[0/1] Oblateness (R_pol_/R_eq_)phys.size;arith.ratiofloatdM/dtRRotational dM/dt correction factorphys.mass.lossfloatvcrit1First critical velocity ({Omega}-limit)km/sphys.velocdoublevcrit2Second critical velocity ({Omega}{Gamma}-limit)km/sphys.velocdoubleOOc[0/1] {Omega}_surf_/{Omega}_crit_stat.fit.paramdoubleGedd[0/1] Eddington factor {Gamma}phys.luminosity;arith.ratiodoubledM/dtmMechanical equatorial dM/dtsolMass/yrphys.mass.lossdoubleLtotTotal angular momentum1e+53g.cm**2.s**-1phys.angMomentumdouble