Show simple item record

dc.creatorPandey, Gajendraen_US
dc.creatorLambert, David L.en_US
dc.date.accessioned2016-04-28T19:34:49Z
dc.date.available2016-04-28T19:34:49Z
dc.date.issued2011-02en
dc.identifierdoi:10.15781/T21N66
dc.identifier.citationPandey, Gajendra, and David L. Lambert. "Neon and CNO Abundances for Extreme Helium StarsラA Non-LTE Analysis." The Astrophysical Journal, Vol. 727, No. 2 (2011): 122.en_US
dc.identifier.issn0004-637Xen_US
dc.identifier.urihttp://hdl.handle.net/2152/34803
dc.description.abstractA non-LTE (NLTE) abundance analysis was carried out for three extreme helium stars (EHes): BD+10 degrees 2179, BD-9 degrees 4395, and LS IV+6 degrees 002, from their optical spectra with NLTE model atmospheres. NLTE TLUSTY model atmospheres were computed with H, He, C, N, O, and Ne treated in NLTE. Model atmosphere parameters were chosen from consideration of fits to observed He I line profiles and ionization equilibria of C and N ions. The program SYNSPEC was then used to determine the NLTE abundances for Ne as well as H, He, C, N, and O. LTE neon abundances from Ne I lines in the EHes: LSE 78, V 1920 Cyg, HD 124448, and PV Tel, are derived from published models and an estimate of the NLTE correction applied to obtain the NLTE Ne abundance. We show that the derived abundances of these key elements, including Ne, are well matched with semi-quantitative predictions for the EHe resulting from a cold merger (i.e., no nucleosynthesis during the merger) of an He white dwarf with a C-O white dwarf.en_US
dc.description.sponsorshipRobert A. Welch Foundation F-634en_US
dc.language.isoEnglishen_US
dc.relation.ispartofen_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.subjectstars: abundancesen_US
dc.subjectstars: atmospheresen_US
dc.subjectstars: chemically peculiaren_US
dc.subjectstars: evolutionen_US
dc.subjectstars: fundamental parametersen_US
dc.subjectcoronae-borealis starsen_US
dc.subjectblanketed model atmospheresen_US
dc.subjecthydrogen-deficienten_US
dc.subjectcarbonen_US
dc.subjectb-type starsen_US
dc.subjectoxygen white-dwarfsen_US
dc.subjectspectral-analysisen_US
dc.subjectgianten_US
dc.subjectbranchen_US
dc.subjectagb starsen_US
dc.subjectstellar atmospheresen_US
dc.subjectelemental abundancesen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleNeon And CNO Abundances For Extreme Helium Stars-A Non-LTE Analysisen_US
dc.typeArticleen_US
dc.description.departmentMcDonald Observatoryen_US
dc.identifier.Filename2011_02_neonandcno.pdfen_US
dc.rights.restrictionOpenen_US
dc.identifier.doi10.1088/0004-637x/727/2/122en_US
dc.contributor.utaustinauthorLambert, David L.en_US
dc.relation.ispartofserialAstrophysical Journalen_US


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record