J/MNRAS/454/1976ivo://CDS.VizieR/J/MNRAS/454/1976doi:10.26093/cds/vizier.74541976CDSReddy A.B.S.Lambert D.L.2024-08-15T20:15:52Z2018-01-22T13:53:23ZCDS support team

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

cds-question@unistra.frstellar-associationsspectroscopyline-intensitieschemical-abundancesWe have observed high-dispersion echelle spectra of main-sequence stars in five nearby young associations - Argus, Carina-Near, Hercules-Lyra, Orion and Subgroup B4 - and derived abundances for elements ranging from Na to Eu. These are the first chemical abundance measurements for two of the five associations, while the remaining three associations are analysed more extensively in our study. Our results support the presence of chemical homogeneity among association members with a typical star-to-star abundance scatter of about 0.06dex or less over many elements. The five associations show log {epsilon}(Li) consistent with their age and share a solar chemical composition for all elements with the exception of Ba. We find that all the heavy elements (Y, Zr, La, Ce, Nd, Sm and Eu) exhibit solar ratios, i.e. [X/Fe]=~0, while Ba is overabundant by about 0.2-0.3dex. The origin of the overabundance of Ba is a puzzle. Within the formulation of the s-process, it is difficult to create a higher Ba abundance without a similar increase in the s-process contributions to other heavy elements (La-Sm). Given that Ba is represented by strong lines of Ba II and La-Sm are represented by rather weak ionized lines, the suggestion, as previously made by other studies, is that the Ba abundance may be systematically overestimated by standard methods of abundance analysis perhaps because the upper reaches of the stellar atmospheres are poorly represented by standard model atmospheres. A novel attempt to analyse the Ba I line at 5535{AA} gives a solar Ba abundance for stars with effective temperatures hotter than about 5800K but increasingly subsolar Ba abundances for cooler stars with apparent Ba deficiencies of 0.5dex at 5100K. This trend with temperature may signal a serious non-local thermodynamical equilibrium effect on the Ba I line.2015MNRAS.454.1976Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/454/1976CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/129/1063 : Abundances of stars within 15pc of the Sun (Luck+, 2005)J/AJ/133/2464 : Parameters and abundances of nearby giants (Luck+, 2007)J/A+A/480/735 : Young local stellar associations (Fernandez+, 2008)J/AJ/142/136 : Spectroscopy of Cepheids. l=30-250{deg} (Luck+, 2011)J/MNRAS/419/1350 : Red giants abundances in 4 open clusters (Reddy+, 2012)J/MNRAS/431/1005 : IC 2391 and Argus young stars (de Silva+, 2013)J/MNRAS/431/3338 : Abundances of red giants in open clusters (Reddy+, 2013)J/A+A/562/A71 : Chemical abundances of solar neighbourhood dwarfsJ/MNRAS/437/2106 : Barium abundance in Galactic Cepheids (Andrievsky+, 2014)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/454/1976https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/454/1976http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/454/1976https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/454/1976https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/454/1976http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/454/1976GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/454/1976/table1 (Targeted stellar associations and their properties from the literature)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/454/1976/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/454/1976/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/454/1976/table1?GETtext/xml+votable180.050000true144.96425-21.57151390.0055555555555555566/17605 20328 21436 24633 26133 31104 36664 39735 40251https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/454/1976?format=asciiOpticaldefaultJ/MNRAS/454/1976/table1Targeted stellar associations and their properties from the literatureStarStar namemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintAssocStellar association namemeta.id.parentcharDistADistance of stellar associationpcpos.distance;pos.heliocentricintAgeAgeMyrtime.ageintRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainl_DistS[~] Limit flag on DistSmeta.code.errorcharDistSDistance of starpcpos.distance;pos.heliocentricfloatSpTSpectral typesrc.spTypecharRef[1/4] Reference for the target selection (1)meta.ref;pos.frameintEWEquivalent widths from table3meta.ref.urlchar[X/Fe]Abundance ratio for this star, from tables 5,6,7meta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/MNRAS/454/1976/table3The line list for all members of associations analysed in this paperrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda[4520.23/8838.43] Wavelength {lambda} ({AA})0.1nmem.wlfloatSpeciesSpecies identification (1)phys.atmol.ionStagefloatLEPLower Excitation potential of the transition (2)eVphys.atmol.excitation;stat.minfloatlog(gf)? Log of the oscillator strengthphys.atmol.oscStrengthfloatnullableEW1? Equivalent width for the star BD-20 2977 (m{AA}) (3)0.1pmspect.line.eqWidthfloatnullableEW2? Equivalent width for the star HD 61005 (m{AA}) (3)0.1pmspect.line.eqWidthfloatnullableEW3? Equivalent width for the star HD 103742 (m{AA}) (3)0.1pmspect.line.eqWidthfloatnullableEW4? Equivalent width for the star HD 103743 (m{AA}) (3)0.1pmspect.line.eqWidthfloatnullableEW5? Equivalent width for the star HD 166 (m{AA}) (3)0.1pmspect.line.eqWidthfloatnullableEW6? Equivalent width for the star HD 10008 (m{AA}) (3)0.1pmspect.line.eqWidthfloatnullableEW7? Equivalent width for the star HD 17925 (m{AA}) (3)0.1pmspect.line.eqWidthfloatnullableEW8? Equivalent width for the star Parenago 2339 (m{AA}) (3)0.1pmspect.line.eqWidthfloatnullableEW9? Equivalent width for the star Parenago 2374 (m{AA}) (3)0.1pmspect.line.eqWidthfloatnullableEW10? Equivalent width for the star HD 113449 (m{AA}) (3)0.1pmspect.line.eqWidthfloatnullableEW11? Equivalent width for the star HD 152555 (m{AA}) (3)0.1pmspect.line.eqWidthfloatnullableJ/MNRAS/454/1976/AbundElemental abundance ratios, [X/Fe], for individual stars (tables 5-7)e_[X/Fe]A? Uncertainty in [X/Fe]Astat.error;phys.abundfloatnullableIonSpecies identifierphys.atmol.ionStagechare_[X/Fe]9? Uncertainty in [X/Fe]9stat.error;phys.abundfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[X/Fe]2? Elemental abundance ratio [X/Fe] for the star HD 61005phys.abund;arith.ratiofloatnullablee_[X/Fe]2? Uncertainty in [X/Fe]2stat.error;phys.abundfloatnullablen_[X/Fe]2[*] Note on [X/Fe]2 (G1)meta.notecharo_[X/Fe]2? Number of lines used in calculating the abundance of that elementmeta.numberintnullable[X/Fe]1? Elemental abundance ratio [X/Fe] for the star BD-20 2977phys.abund;arith.ratiofloatnullablee_[X/Fe]1? Uncertainty in [X/Fe]1stat.error;phys.abundfloatnullablen_[X/Fe]1[*] Note on [X/Fe]1 (G1)meta.notecharo_[X/Fe]1? Number of lines used in calculating the abundance of that elementmeta.numberintnullable[X/Fe]A? Average elemental abundance ratio [X/Fe] for the Argus associationphys.abund;arith.ratiofloatnullablen_[X/Fe]A[*] Note on [X/Fe]A (G1)meta.notechar[X/Fe]3? Elemental abundance ratio [X/Fe] for the star HD 103742phys.abund;arith.ratiofloatnullablee_[X/Fe]3? Uncertainty in [X/Fe]3stat.error;phys.abundfloatnullablen_[X/Fe]3[*] Note on [X/Fe]3 (G1)meta.notecharo_[X/Fe]3? Number of lines used in calculating the abundance of that elementmeta.numberintnullable[X/Fe]4? Elemental abundance ratio [X/Fe] for the star HD 103743phys.abund;arith.ratiofloatnullablee_[X/Fe]4? Uncertainty in [X/Fe]4stat.error;phys.abundfloatnullablen_[X/Fe]4[*] Note on [X/Fe]4 (G1)meta.notecharo_[X/Fe]4? Number of lines used in calculating the abundance of that elementmeta.numberintnullable[X/Fe]C? Average elemental abundance ratio [X/Fe] for the Carina-Near associationphys.abund;arith.ratiofloatnullablee_[X/Fe]C? Uncertainty in [X/Fe]Cstat.error;phys.abundfloatnullablen_[X/Fe]C[*] Note on [X/Fe]C (G1)meta.notechar[X/Fe]8? Elemental abundance ratio [X/Fe] for the star Parenago 2339phys.abund;arith.ratiofloatnullablee_[X/Fe]8? Uncertainty in [X/Fe]8stat.error;phys.abundfloatnullablen_[X/Fe]8[*] Note on [X/Fe]8 (G1)meta.notecharo_[X/Fe]8? Number of lines used in calculating the abundance of that elementmeta.numberintnullable[X/Fe]9? Elemental abundance ratio [X/Fe] for the star Parenago 2374phys.abund;arith.ratiofloatnullablen_[X/Fe]9[*] Note on [X/Fe]9 (G1)meta.notecharo_[X/Fe]9? Number of lines used in calculating the abundance of that elementmeta.numberintnullable[X/Fe]O? Average elemental abundance ratio [X/Fe] for the Orion associationphys.abund;arith.ratiofloatnullablee_[X/Fe]O? Uncertainty in [X/Fe]Ostat.error;phys.abundfloatnullablen_[X/Fe]O[*] Note on [X/Fe]O (G1)meta.notechar[X/Fe]10? Elemental abundance ratio [X/Fe] for the star HD 113449phys.abund;arith.ratiofloatnullablee_[X/Fe]10? Uncertainty in [X/Fe]10stat.error;phys.abundfloatnullablen_[X/Fe]10[*] Note on [X/Fe]10 (G1)meta.notecharo_[X/Fe]10? Number of lines used in calculating the abundance of that elementmeta.numberintnullable[X/Fe]11? Elemental abundance ratio [X/Fe] for the star HD 152555phys.abund;arith.ratiofloatnullablee_[X/Fe]11? Uncertainty in [X/Fe]11stat.error;phys.abundfloatnullablen_[X/Fe]11[*] Note on [X/Fe]11 (G1)meta.notecharo_[X/Fe]11? Number of lines used in calculating the abundance of that elementmeta.numberintnullable[X/Fe]S? Average elemental abundance ratio [X/Fe] for the Subgroup B4 associationphys.abund;arith.ratiofloatnullablee_[X/Fe]S? Uncertainty in [X/Fe]Sstat.error;phys.abundfloatnullablen_[X/Fe]S[*] Note on [X/Fe]S (G1)meta.notechar[X/Fe]5? Elemental abundance ratio [X/Fe] for the star HD 166phys.abund;arith.ratiofloatnullablee_[X/Fe]5? Uncertainty in [X/Fe]5stat.error;phys.abundfloatnullablen_[X/Fe]5[*] Note on [X/Fe]5 (G1)meta.notecharo_[X/Fe]5? Number of lines used in calculating the abundance of that elementmeta.numberintnullable[X/Fe]6? Elemental abundance ratio [X/Fe] for the star HD 10008phys.abund;arith.ratiofloatnullablee_[X/Fe]6? Uncertainty in [X/Fe]6stat.error;phys.abundfloatnullablen_[X/Fe]6[*] Note on [X/Fe]6 (G1)meta.notecharo_[X/Fe]6? Number of lines used in calculating the abundance of that elementmeta.numberintnullable[X/Fe]7? Elemental abundance ratio [X/Fe] for the star HD 17925phys.abund;arith.ratiofloatnullablee_[X/Fe]7? Uncertainty in [X/Fe]7stat.error;phys.abundfloatnullablen_[X/Fe]7[*] Note on [X/Fe]7 (G1)meta.notecharo_[X/Fe]7? Number of lines used in calculating the abundance of that elementmeta.numberintnullable[X/Fe]H? Average elemental abundance ratio [X/Fe] for the Hercules-Lyra associationphys.abund;arith.ratiofloatnullablee_[X/Fe]H? Uncertainty in [X/Fe]Hstat.error;phys.abundfloatnullablen_[X/Fe]H[*] Note on [X/Fe]H (G1)meta.notecharJ/MNRAS/454/1976/table9Mean abundance ratios, [X/Fe], for the Argus, Carina-Near, Hercules-Lyra, Orion and Subgroup B4 associationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIonSpecies identifierphys.atmol.ionStagechar[X/Fe]A? Mean abundance ratio [X/Fe] for the Argus associationphys.abund;arith.ratiofloatnullablee_[X/Fe]A? Uncertainty in [X/Fe]Astat.error;phys.abundfloatnullablen_[X/Fe]A[*] Note on [X/Fe]A (G1)meta.notechar[X/Fe]CMean abundance ratio [X/Fe] for the Carina-Near associationphys.abund;arith.ratiofloate_[X/Fe]C? Uncertainty in [X/Fe]Cstat.error;phys.abundfloatnullablen_[X/Fe]C[*] Note on [X/Fe]C (G1)meta.notechar[X/Fe]HMean abundance ratio [X/Fe] for the Hercules-Lyra associationphys.abund;arith.ratiofloate_[X/Fe]H? Uncertainty in [X/Fe]Hstat.error;phys.abundfloatnullablen_[X/Fe]H[*] Note on [X/Fe]H (G1)meta.notechar[X/Fe]O? Mean abundance ratio [X/Fe] for the Orion associationphys.abund;arith.ratiofloatnullablee_[X/Fe]O? Uncertainty in [X/Fe]Ostat.error;phys.abundfloatnullablen_[X/Fe]O[*] Note on [X/Fe]O (G1)meta.notechar[X/Fe]S? Mean abundance ratio [X/Fe] for the Subgroup B4 associationphys.abund;arith.ratiofloatnullablee_[X/Fe]S? Uncertainty in [X/Fe]Sstat.error;phys.abundfloatnullablen_[X/Fe]S[*] Note on [X/Fe]S (G1)meta.notecharJ/MNRAS/454/1976/table11Mean elemental abundance ratios, [X/Fe], for our five associations and the comparison samplesIonSpecies identifierphys.atmol.ionStagecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[X/Fe]MMean elemental abundance ratio [X/Fe] for our sample of five associationsphys.abund;arith.ratiofloate_[X/Fe]MUncertainty in [X/Fe]Mstat.error;phys.abundfloat[X/Fe]d1? Thin disc mean elemental abundance ratio [X/Fe] for field dwarfs (1)phys.abund;arith.ratiofloatnullablee_[X/Fe]d1? Uncertainty in [X/Fe]d1 (1)stat.error;phys.abundfloatnullable[X/Fe]d2? Thin disc mean elemental abundance ratio [X/Fe] for field dwarfs (2)phys.abund;arith.ratiofloatnullablee_[X/Fe]d2? Uncertainty in [X/Fe]d2 (2)stat.error;phys.abundfloatnullable[X/Fe]r1? Thin disc mean elemental abundance ratio [X/Fe] for red giants in OCs (3)phys.abund;arith.ratiofloatnullablee_[X/Fe]r1? Uncertainty in [X/Fe]r1 (3)stat.error;phys.abundfloatnullable[X/Fe]r2? Thin disc mean elemental abundance ratio [X/Fe] for red giants (4)phys.abund;arith.ratiofloatnullablee_[X/Fe]r2? Uncertainty in [X/Fe]r2 (4)stat.error;phys.abundfloatnullable[X/Fe]CeThin disc mean elemental abundance ratio [X/Fe] for Cepheids (5)phys.abund;arith.ratiofloate_[X/Fe]CeUncertainty in [X/Fe]Ce (5)stat.error;phys.abundfloatr_[X/Fe]CeReference for [X/Fe]Ce (6)meta.ref;pos.framechar