J/A+A/631/A171ivo://CDS.VizieR/J/A+A/631/A171doi:10.26093/cds/vizier.36310171CDSSkuladottir A.Hansen C.JSalvadori S.Choplin A.2022-08-25T11:34:10Z2019-11-19T08:25:54ZCDS support team

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

cds-question@unistra.frgalaxieschemical-abundancesThe heavy elements (Z>30) are created in neutron (n)-capture processes which are predicted to happen at vastly different nucleosynthetic sites. To study these processes in an environment different from the Milky Way, we target the n-capture elements in red giant branch stars in the Sculptor dwarf spheroidal galaxy. Using ESO VLT/FLAMES spectra, we measure the chemical abundances of Y, Ba, La, Nd, and Eu, in 98 stars covering the metalliticy range -2.4<[Fe/H]<-0.9. This is the first paper in a series about the n-capture elements in dwarf galaxies, and here we focus on the relative and absolute timescales of the slow (s)- and rapid (r)- processes in Sculptor. From the abundances of the s-process element Ba and the r-process element Eu, it is clear that the r-process enrichment occurred throughout the entire chemical evolution history of Sculptor. Furthermore, there is no evidence for the r-process to have a significant time delay relative to core-collapse supernovae. Neutron star mergers are therefore unlikely the dominant (or only) nucleosynthetic site of the r-process. However, the products of the s-process only become apparent at [Fe/H]~=-2 in Sculptor, and the s-process becomes the dominant source of Ba at [Fe/H]>~-2. We test the use of [Y/Mg] and [Ba/Mg] as chemical clocks in Sculptor. Similarly to what is observed in the Milky Way, [Y/Mg] and [Ba/Mg] increase towards younger ages. However, there is an offset in the trends, where the abundance ratios of [Y/Mg] in Sculptor are significantly lower than those of the Milky Way at any given age. This is most likely caused by metallicity dependence of yields from the s-process, as well as different relative contribution of the s-process to core-collapse supernovae in these galaxies. Comparisons of our data with that of the Milky Way and the Fornax dwarf spheroidal galaxy furthermore show that these chemical clocks are both metallicity and environment dependent.2019A&A...631A.171Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/631/A171CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/383/183 : CaII triplet of RGB from VLT/FLAMES obs. (Battaglia+, 2008)J/A+A/574/A129 : The First CEMP star in the Sculptor dSph (Skuladottir+, 2015)J/A+A/580/A129 : Sulphur in the Sculptor dSph (Skuladottir+, 2015)J/A+A/606/A71 : dSph RGB abundance and velocities (Skuladottir+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/631/A171https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/631/A171http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/631/A171https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/631/A171https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/631/A171http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/631/A171GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/631/A171/tableb1 (Atmospheric parameters and chem. abundances)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/631/A171/tableb1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/631/A171/tableb1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/631/A171/tableb1?GETtext/xml+votable180.050000true15.22575-32.67072220.0055555555555555566/35549 35720 35722https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/631/A171?format=asciidefaultJ/A+A/631/A171/tableb1Atmospheric parameters and chem. abundancesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarName of starmeta.id;meta.maincharRAJ2000Right ascension (J2000.0)pos.eq.ra;meta.mainDEJ2000Declination (J2000.0)pos.eq.dec;meta.mainTeffEffective TemperatureKphys.temperature.effectiveintlog(g)Surface gravitylog(cm.s**-2)phys.gravityfloatvtMicroturbulence velocitykm/sphys.veloc.microTurbfloat[Fe/H]Abundance [Fe/H]phys.abund.Fefloate_[Fe/H]Error on [Fe/H]stat.error;phys.abund.Fefloato_MgNumber of measured Mg linesmeta.numberint[Mg/Fe]? Abundance [Mg/Fe]phys.abundfloatnullablee_[Mg/Fe]? Error on [Mg/Fe]stat.error;phys.abundfloatnullableo_YNumber of measured Y linesmeta.numberint[Y/Fe]? Abundance [Y/Fe]phys.abundfloatnullablee_[Y/Fe]? Error on [Y/Fe]stat.error;phys.abundfloatnullableo_BaNumber of measured Ba linesmeta.numberint[Ba/Fe]Abundance [Ba/Fe]phys.abundfloate_[Ba/Fe]Error on [Ba/Fe]stat.error;phys.abundfloato_LaNumber of measured La linesmeta.numberint[La/Fe]? Abundance [La/Fe]phys.abundfloatnullablee_[La/Fe]? Error on [La/Fe]stat.error;phys.abundfloatnullableo_NdNumber of measured Nd linesmeta.numberint[Nd/Fe]? Abundance [Nd/Fe]phys.abundfloatnullablee_[Nd/Fe]? Error on [Nd/Fe]stat.error;phys.abundfloatnullableSimbadSimbad column added by the CDSmeta.ref.urlcharo_EuNumber of measured Eu linesmeta.numberint[Eu/Fe]? Abundance [Eu/Fe]phys.abundfloatnullablee_[Eu/Fe]? Error on [Eu/Fe]stat.error;phys.abundfloatnullableJ/A+A/631/A171/tableb2LinelistIonElemental ionphys.atmol.ionStagecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambdaWavelength0.1nmem.wldoubleChiexExcitation potentialphys.atmol.excitationfloatlog(gf)Oscillator strengthphys.atmol.oscStrengthfloatInst[G/U] GIRAFFE/UVESmeta.id;instrchar