Oxygen Isotopic Ratios In Cool R Coronae Borealis Stars

dc.contributor.utaustinauthorLambert, David L.en_US
dc.creatorGarcia-Hernandez, D. Anibalen_US
dc.creatorLambert, David L.en_US
dc.creatorRao, N. Kameswaraen_US
dc.creatorHinkle, Ken. H.en_US
dc.creatorEriksson, Kiellen_US
dc.date.accessioned2016-04-28T19:33:55Z
dc.date.available2016-04-28T19:33:55Z
dc.date.issued2010-05en
dc.description.abstractWe investigate the relationship between R Coronae Borealis (RCB) stars and hydrogen-deficient carbon (HdC) stars by measuring precise (16)O/(18)O ratios for five cool RCB stars. The (16)O/(18)O ratios are derived by spectrum synthesis from high-resolution (R similar to 50,000) K-band spectra. Lower limits to the (16)O/(17)O and (14)N/(15)N ratios as well as Na and S abundances (when possible) are also given. RCB stars in our sample generally display less (18)O than HdC stars-the derived (16)O/(18)O ratios range from 3 to 20. The only exception is the RCB star WX CrA, which seems to be an HdC-like star with (16)O/(18)O = 0.3. Our result of a higher (16)O/(18)O ratio for the RCB stars must be accounted for by a theory of the formation and evolution of HdC and RCB stars. We speculate that a late dredge-up of products of He burning, principally (12)C and (16)O, may convert an (18)O-rich HdC star into an (18)O-poor RCB star as the H-deficient star begins its final evolution from a cool supergiant to the top of the white dwarf cooling track.en_US
dc.description.departmentMcDonald Observatoryen_US
dc.description.sponsorshipSpanish Ministry of Science and Innovation (MICINN) AYA-2007-64748en_US
dc.description.sponsorshipRobert A. Welch Foundation of Houston, Texas F-634en_US
dc.description.sponsorshipSwedish Research Councilen_US
dc.identifierdoi:10.15781/T23R5G
dc.identifier.Filename2010_05_oxygenisotopic.pdfen_US
dc.identifier.citationGarcia-Hernandez, D. Anibal, David L. Lambert, N. Kameswara Rao, Ken H. Hinkle, and Kjell Eriksson. "Oxygen isotopic ratios in cool R Coronae Borealis stars." The Astrophysical Journal, Vol. 714, No. 1 (May., 2010): 144.en_US
dc.identifier.doi10.1088/0004-637x/714/1/144en_US
dc.identifier.issn0004-637Xen_US
dc.identifier.urihttp://hdl.handle.net/2152/34756
dc.language.isoEnglishen_US
dc.relation.ispartofen_US
dc.relation.ispartofserialAstrophysical 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.rights.restrictionOpenen_US
dc.subjectinfrared: starsen_US
dc.subjectstars: abundancesen_US
dc.subjectstars: atmospheresen_US
dc.subjectstars:en_US
dc.subjectchemically peculiaren_US
dc.subjectwhite dwarfsen_US
dc.subjecthydrogen-deficient carbonen_US
dc.subjectextreme helium starsen_US
dc.subjectwhite-dwarfsen_US
dc.subjectevolutionen_US
dc.subjectabundancesen_US
dc.subjectsupernovaeen_US
dc.subjecto-18en_US
dc.subjectastronomy & astrophysicsen_US
dc.titleOxygen Isotopic Ratios In Cool R Coronae Borealis Starsen_US
dc.typeArticleen_US
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