Chemical Abundances For Evolved Stars In M5: Lithium Through Thorium

dc.contributor.utaustinauthorSneden, Christopheren_US
dc.creatorLai, David K.en_US
dc.creatorSmith, Graeme H.en_US
dc.creatorBolte, Michaelen_US
dc.creatorJohnson, Jennifer A.en_US
dc.creatorLucatello, Saraen_US
dc.creatorKraft, Robert P.en_US
dc.creatorSneden, Christopheren_US
dc.description.abstractWe present analysis of high-resolution spectra of a sample of stars in the globular cluster M5 (NGC 5904). The sample includes stars from the red giant branch (RGB; seven stars), the red horizontal branch (two stars), and the asymptotic giant branch (AGB; eight stars), with effective temperatures ranging from 4000 K to 6100 K. Spectra were obtained with the HIRES spectrometer on the Keck I telescope, with a wavelength coverage from 3700 angstrom to 7950 angstrom for the HB and AGB sample, and 5300 angstrom to 7600 angstrom for the majority of the RGB sample. We find offsets of some abundance ratios between the AGB and the RGB branches. However, these discrepancies appear to be due to analysis effects, and indicate that caution must be exerted when directly comparing abundance ratios between different evolutionary branches. We find the expected signatures of pollution from material enriched in the products of the hot hydrogen burning cycles such as the CNO, Ne-Na, and Mg-Al cycles, but no significant differences within these signatures among the three stellar evolutionary branches especially when considering the analysis offsets. We are also able to measure an assortment of neutron-capture element abundances, from Sr to Th, in the cluster. We find that the neutron-capture signature for all stars is the same, and shows a predominately r-process origin. However, we also see evidence of a small but consistent extra s-process signature that is not tied to the light-element variations, pointing to a pre-enrichment of this material in the protocluster gas.en_US
dc.description.sponsorshipNational Science Foundation AST-0802292en_US
dc.description.sponsorshipNSF AST-0406988, AST-0607770, AST-0607482en_US
dc.description.sponsorshipW. M. Keck Foundationen_US
dc.identifier.citationLai, David K., Graeme H. Smith, Michael Bolte, Jennifer A. Johnson, Sara Lucatello, Robert P. Kraft, and Christopher Sneden. >Chemical abundances for evolved stars in M5: lithium through thorium.> The Astronomical Journal 141, No. 2 (Feb., 2011): 62.en_US
dc.relation.ispartofserialAstronomical Journalen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.subjectglobular clusters: individual (ngc 5904)en_US
dc.subjectstars: abundancesen_US
dc.subjectstars: agben_US
dc.subjectand post-agben_US
dc.subjectmetal-poor starsen_US
dc.subjectasymptotic giant branchen_US
dc.subjectglobular-cluster m5en_US
dc.subjectexperimental oscillator-strengthsen_US
dc.subjectrr lyrae variablesen_US
dc.subjectred gianten_US
dc.subjectbright giantsen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleChemical Abundances For Evolved Stars In M5: Lithium Through Thoriumen_US

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