SIMBAD references

2021ApJ...908...79G - Astrophys. J., 908, 79-79 (2021/February-2)

The r-process Alliance: chemodynamically tagged groups of halo r-process-enhanced stars reveal a shared chemical-evolution history.

GUDIN D., SHANK D., BEERS T.C., YUAN Z., LIMBERG G., ROEDERER I.U., PLACCO V., HOLMBECK E.M., DIETZ S., RASMUSSEN K.C., HANSEN T.T., SAKARI C.M., EZZEDDINE R. and FREBEL A.

Abstract (from CDS):

We derive dynamical parameters for a large sample of 446 r-process-enhanced (RPE) metal-poor stars in the halo and disk systems of the Milky Way, based on data releases from the R-Process Alliance, supplemented by additional literature samples. This sample represents more than a 10-fold increase in size relative to that previously considered by Roederer et al. and, by design, covers a larger range of r-process-element enrichment levels. We test a number of clustering analysis methods on the derived orbital energies and other dynamical parameters for this sample, ultimately deciding on application of the HDBSCAN algorithm, which obtains 30 individual chemodynamically tagged groups (CDTGs); 21 contain between 3 and 5 stars, and 9 contain between 6 and 12 stars. Even though the clustering was performed solely on the basis of their dynamical properties, the stars in these CDTGs exhibit statistically significant similarities in their metallicity ([Fe/H]), carbonicity ([C/Fe]), and neutron-capture element ratios ([Sr/Fe], [Ba/Fe], and [Eu/Fe]). These results demonstrate that the RPE stars in these CDTGs have likely experienced common chemical-evolution histories, presumably in their parent satellite galaxies or globular clusters, prior to being disrupted into the Milky Way's halo. We also confirm the previous claim that the orbits of the RPE stars preferentially exhibit pericentric distances that are substantially lower than the present distances of surviving ultrafaint dwarf and canonical dwarf spheroidal galaxies, consistent with the disruption hypothesis. The derived dynamical parameters for several of our CDTGs indicate their association with previously known substructures, dynamically tagged groups, and RPE groups.

Abstract Copyright: © 2021. The American Astronomical Society. All rights reserved.

Journal keyword(s): Dwarf galaxies - Milky Way stellar halo - Stellar dynamics - Stellar abundances - Stellar populations - R-process

VizieR on-line data: <Available at CDS (J/ApJ/908/79): table2.dat table3.dat table4.dat table5.dat>

Nomenclature: Tables 5-6: [GSB2021] CDTG-NN (Nos 1-30).

CDS comments: Substructures from table 8 and CDTGs groups from table 6 are not in SIMBAD.

Simbad objects: 46

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