J/A+A/640/A81ivo://CDS.VizieR/J/A+A/640/A81doi:10.26093/cds/vizier.36400081CDSNissen P.E.Christensen-Dalsgaard J.Mosumgaard J.R.Silva Aguirre V.,Spitoni E.Verma K.2021-11-29T07:35:20Z2020-08-17T08:35:11ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyg-starschemical-abundancesPrevious high-precision studies of abundances of elements in solar twin stars are extended to a wider metallicity range to see how the trends of element ratios with stellar age depend on [Fe/H]. HARPS spectra with S/N>~600 at {lambda}~6000{AA} were analysed with MARCS model atmospheres to obtain 1D LTE abundances of C, O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Sr, and Y in 72 solar-type stars including the binary star zeta Reticuli and ASTEC stellar models were used to determine stellar ages from effective temperatures, luminosities obtained via Gaia DR2 parallaxes, and heavy element abundances. The age-metallicity distribution appears to consist of the following two distinct populations: a sequence of old stars with a steep rise of [Fe/H] to ~+0.3 dex at an age of ~7Gyr and a younger sequence with [Fe/H] increasing from about -0.3dex to ~+0.2dex over the last 6Gyr. Furthermore, the trends of several abundance ratios, [O/Fe], [Na/Fe], [Ca/Fe], and [Ni/Fe], as a function of stellar age, split into two corresponding sequences. The [Y/Mg]-age relation, on the other hand, shows no offset between the two age sequences and has no significant dependence on [Fe/H], but the components of a visual binary star, {zeta} Reticuli, have a large and puzzling deviation. The split of the age-metallicity distribution into two sequences may be interpreted as evidence of two episodes of accretion of gas onto the Galactic disk with a quenching of star formation in between. Some of the [X/Fe]-age relations support this scenario but other relations are not so easy to explain, which calls for a deeper study of systematic errors in the derived abundances as a function of [Fe/H], in particular 3D non-LTE effects.2020A&A...640A..81Nhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/640/A81CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/105/2299 : Li abundance of solar-type stars. II. (Soderblom+, 1993)J/A+A/327/587 : Abundances of 9 solar-type stars (Tomkin+ 1997)J/PASJ/57/65 : CNO abundances of solar-type stars (Takeda+, 2005)J/A+A/468/663 : Li abundances in solar-analog stars (Takeda+, 2007)J/A+A/508/L17 : Abundances in solar analogs (Ramirez+, 2009)J/A+A/515/A93 : Li abundances in solar-analog stars. II. (Takeda+, 2010)J/ApJ/839/94 : Abundances of solar twins from Keck/HIRES (Bedell+, 2017)J/ApJ/865/68 : Abundances for 79 Sun-like stars within 100pc (Bedell+, 2018)J/MNRAS/423/122 : Abundances of 93 solar-type Kepler targets (Bruntt+, 2012)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/640/A81https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/640/A81http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/640/A81https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/640/A81https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/640/A81http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/640/A81GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/640/A81/table1 (Stellar parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/640/A81/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/640/A81/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/640/A81/table1?GETtext/xml+votable180.050000true2.0681742-14.82449190.0055555555555555566/4128 15174 17177 17266 17341 17419 17540 17572 17804 17944 20593 21121 21400 21484 21516 21906 22746 23123 23177 24769 25078 25424 25567 26652 26768 29900 30878 33219 33552 34983 35121 35230 35954 36590 36635 37944 37954 38099 38238 38279 38562 39576 39693 39767 40105 40317 41094 41204 41912 42157 42248 43258 43544 43813 43977 44131 44243 45627 45668 46056 46193 46247 46681 46734 47590 48519 48607 48821 48943 49114https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/640/A81?format=asciidefaultJ/A+A/640/A81/table1Stellar parametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHDHD numbermeta.id;meta.mainintTeffEffective temperatureKphys.temperature.effectiveintlogg-splogarithmic spectroscopic gravitylog(cm.s**-2)phys.gravitydoubleVturbMicroturbulence parameterkm/sstat.paramfloat[Fe/H]Logarithmic Fe/H ratiolog(Sun)phys.abund.Fe;arith.ratiodouble[alpha/Fe]Logarithmic alpha/Fe ratiolog(Sun)phys.abunddoubleZsStellar surface heavy element fractionphys.abund.ZdoublelogLLogarithmic stellar luminositylog(Sun)phys.luminositydoubleAgeStellar ageGyrtime.agefloate_Age1-sigma error of stellar ageGyrstat.error;time.agefloatMassStellar masslog(Sun)phys.massfloatlogg-phlogarithmic photometric gravitylog(cm.s**-2)phys.gravityfloatYsStellar surface helium fractionphys.abund.YfloatSimbadSimbad 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.mainJ/A+A/640/A81/table2Abundance ratiosrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHDHD numbermeta.id;meta.mainint[C/Fe]Logarithmic C/Fe ratiolog(Sun)phys.massdouble[O/Fe]Logarithmic O/Fe ratiolog(Sun)phys.massdouble[Na/Fe]Logarithmic Na/Fe ratiolog(Sun)phys.massdouble[Mg/Fe]Logarithmic Mg/Fe ratiolog(Sun)phys.massdouble[Al/Fe]Logarithmic Al/Fe ratiolog(Sun)phys.massdouble[Si/Fe]Logarithmic Si/Fe ratiolog(Sun)phys.massdouble[Ca/Fe]Logarithmic Ca/Fe ratiolog(Sun)phys.massdouble[Ti/Fe]Logarithmic Ti/Fe ratiolog(Sun)phys.massdouble[Cr/Fe]Logarithmic Cr/Fe ratiolog(Sun)phys.massdouble[Ni/Fe]Logarithmic Ni/Fe ratiolog(Sun)phys.massdouble[Sr/Fe]Logarithmic Ni/Fe ratiolog(Sun)phys.massdouble[Y/Fe]Logarithmic Y/Fe ratiolog(Sun)phys.massdouble