J/A+A/704/A282ivo://CDS.VizieR/J/A+A/704/A282CDSRacca M.Hansen T.T.Roederer I.U.Placco V.M.Frebel A.Beers T.C.,Ezzeddine R.Holmbeck E.M.Sakari C.M.Monty S.Harket O.Simon J.D.,Sneden C.Thompson I.B.2026-03-02T06:25:50Z2025-12-17T08:32:29ZCDS support team

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

cds-question@unistra.frchemically-peculiar-starspopulation-ii-starschemical-abundancesThe astrophysical origin of the rapid neutron-capture process (r-process), responsible for producing roughly half of the elements heavier than iron, remains uncertain. Detailed chemical signatures from the oldest, most metal-poor stars, which act as fossil records of the earliest nucleosynthesis events, can be used to identify the dominant r-process sites. We present a homogeneous chemical abundance analysis of ten r-process element-enhanced stars. These old and metal-poor stars are strongly enriched in r-process elements with minimal contamination from other nucleosynthetic sources. By focusing on this chemically pure sample, we aim to investigate intrinsic variations in the r-process abundance patterns and explore their implications for the nature and potential diversity of r-process sites. We performed a detailed chemical abundance analysis of high-resolution, high signal-to-noise spectra. For each star, we inspected over 1400 individual absorption lines using a combination of equivalent width measurements and spectral synthesis. The analysis was conducted under the assumption of one-dimensional local thermodynamic equilibrium, employing the MOOG radiative transfer code. We derived abundances for 54 chemical species, including 29 neutron-capture (n-capture) elements covering the full mass range of the r-process abundance pattern. A kinematic analysis reveals that stars likely originated from ten kinematically distinct systems. Based on this assumption, we use the sample to probe the maximum variation expected from ten independent r-process nucleosynthesis events and compute the intrinsic dispersion of each element relative to Zr and Eu, for the light and heavy r-process elements, respectively. This exercise results in a remarkably low cosmic scatter across the ten r-process sites enriching these stars, for the rare earth and third peak elements, for example, we find {sigma}[La/Eu]=0.08 and {sigma}[Os/Eu]=0.11dex while the scatter between light and heavy, {sigma}[Zr/Eu] is slightly higher at 0.18dex. The elemental abundance patterns across the ten independent r-process sites show remarkably small cosmic dispersions. This minimal dispersion suggests a high degree of uniformity in r-process yields across diverse astrophysical environments.2025A&A...704A.282Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/704/A282CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/704/A282https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/704/A282http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/704/A282https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/704/A282https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/704/A282http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/704/A282GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/704/A282/table1 (Properties of the stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/704/A282/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/704/A282/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/704/A282/table1?GETtext/xml+votable180.050000true10.05208327.4901940.0055555555555555566/19963 36458 36642 43367 44573 45309 46026 47201 47608 489267.952274030004205e-20 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/704/A282?format=asciidefaultJ/A+A/704/A282/table1Properties of the starsrecnoRecord number assigned by the VizieR team. 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Equivalent width (for eqw lines; '--' for syn)0.1pmspect.line.eqWidthfloatnullablelog(eps)? Derived abundancephys.abundfloatnullableRef? Literature source of log(gf)meta.bibintnullableJ/A+A/704/A282/rlj14m23J1430-2371 all spectral lines used in the abundance analysisEP? Excitation potentialeVphys.atmol.excitationfloatnullableloggf? Oscillator strengthphys.atmol.oscStrengthfloatnullableMethodMethod (1)meta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambdaWavelength0.1nmem.wlfloatEW? Equivalent width (for eqw lines; '--' for syn)0.1pmspect.line.eqWidthfloatnullablelog(eps)? Derived abundancephys.abundfloatnullableRef? Literature source of log(gf)meta.bibintnullableSpeciesElement and ionization stagephys.atmol.ionStage;phys.atmol.ionizationcharJ/A+A/704/A282/rlj14m41J1432-4125 all spectral lines used in the abundance analysisrecnoRecord number assigned by the VizieR team. 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Equivalent width (for eqw lines; '--' for syn)0.1pmspect.line.eqWidthfloatnullablelog(eps)? Derived abundancephys.abundfloatnullableRef? Literature source of log(gf)meta.bibintnullableJ/A+A/704/A282/rlj20m34J2009-3410 all spectral lines used in the abundance analysisrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambdaWavelength0.1nmem.wlfloatSpeciesElement and ionization stagephys.atmol.ionStage;phys.atmol.ionizationcharEP? Excitation potentialeVphys.atmol.excitationfloatnullableloggf? Oscillator strengthphys.atmol.oscStrengthfloatnullableMethodMethod (1)meta.notecharEW? Equivalent width (for eqw lines; '--' for syn)0.1pmspect.line.eqWidthfloatnullablelog(eps)? Derived abundancephys.abundfloatnullableRef? Literature source of log(gf)meta.bibintnullableJ/A+A/704/A282/rlj20m51J2049-5124 all spectral lines used in the abundance analysisrecnoRecord number assigned by the VizieR team. 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Uncertainty in [X/Fe]stat.error;phys.abundfloatnullableJ/A+A/704/A282/abj19m55J1916-5544 all detected elements from light to neutron-capture speciesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSpeciesSpeciesmeta.notefloatElElementphys.atmol.elementcharNlinesNumber of transitions usedmeta.id;instr.setupintlog(eps)Mean abundancephys.abundfloat[X/H]Abundance relative to solarphys.abundfloate_[X/H]? Uncertainty in [X/H]stat.error;phys.abundfloatnullable[X/Fe]Abundance relative to ironphys.abundfloate_[X/Fe]? Uncertainty in [X/Fe]stat.error;phys.abundfloatnullableJ/A+A/704/A282/abj20m34J2009-3410 all detected elements from light to neutron-capture speciesNlinesNumber of transitions usedmeta.id;instr.setupintlog(eps)Mean abundancephys.abundfloat[X/H]Abundance relative to solarphys.abundfloate_[X/H]? Uncertainty in [X/H]stat.error;phys.abundfloatnullable[X/Fe]Abundance relative to ironphys.abundfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSpeciesSpeciesmeta.notefloatElElementphys.atmol.elementchare_[X/Fe]? Uncertainty in [X/Fe]stat.error;phys.abundfloatnullableJ/A+A/704/A282/abj20m51J2049-5124 all detected elements from light to neutron-capture speciesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSpeciesSpeciesmeta.notefloatElElementphys.atmol.elementcharNlinesNumber of transitions usedmeta.id;instr.setupintlog(eps)Mean abundancephys.abundfloat[X/H]Abundance relative to solarphys.abundfloate_[X/H]? Uncertainty in [X/H]stat.error;phys.abundfloatnullable[X/Fe]Abundance relative to ironphys.abundfloate_[X/Fe]? Uncertainty in [X/Fe]stat.error;phys.abundfloatnullableJ/A+A/704/A282/abj21m13J2109-1310 all detected elements from light to neutron-capture speciesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSpeciesSpeciesmeta.notefloatElElementphys.atmol.elementcharNlinesNumber of transitions usedmeta.id;instr.setupintlog(eps)Mean abundancephys.abundfloat[X/H]Abundance relative to solarphys.abundfloate_[X/H]? Uncertainty in [X/H]stat.error;phys.abundfloatnullable[X/Fe]Abundance relative to ironphys.abundfloate_[X/Fe]? Uncertainty in [X/Fe]stat.error;phys.abundfloatnullableJ/A+A/704/A282/abj21m68J2106-6828 all detected elements from light to neutron-capture speciesrecnoRecord number assigned by the VizieR team. 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