Hubble Space Telescope Near-Ultraviolet Spectroscopy Of The Bright CEMP-No Star BD+44 Degrees 493

dc.contributor.utaustinauthorSneden, Christopheren_US
dc.creatorPlacco, Vinicius M.en_US
dc.creatorBeers, Timothy C.en_US
dc.creatorRoederer, Ian U.en_US
dc.creatorCowan, John J.en_US
dc.creatorFrebel, Annaen_US
dc.creatorFiller, Danen_US
dc.creatorIvans, Inese I.en_US
dc.creatorLawler, James E.en_US
dc.creatorSchatz, Hendriken_US
dc.creatorSneden, Christopheren_US
dc.creatorSobeck, Jennifer S.en_US
dc.creatorAoki, Wakoen_US
dc.creatorSmith, Verne V.en_US
dc.description.abstractWe present an elemental-abundance analysis, in the near-ultraviolet (NUV) spectral range, for the extremely metal-poor star BD+44 degrees 493 a ninth magnitude subgiant with [Fe/H] = -3.8 and enhanced carbon, based on data acquired with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. This star is the brightest example of a class of objects that, unlike the great majority of carbon-enhanced metal-poor (CEMP) stars, does not exhibit over-abundances of heavy neutron-capture elements (CEMP-no). In this paper, we validate the abundance determinations for a number of species that were previously studied in the optical region, and obtain strong upper limits for beryllium and boron, as well as for neutron-capture elements from zirconium to platinum, many of which are not accessible from ground-based spectra. The boron upper limit we obtain for BD+44 degrees 493, log is an element of (B) < -0.70, the first such measurement for a CEMP star, is the lowest yet found for very and extremely metal-poor stars. In addition, we obtain even lower upper limits on the abundances of beryllium, log is an element of (Be) < -2.3, and lead, log is an element of (Pb) < -0.23 ([Pb/Fe] < +1.90), than those reported by previous analyses in the optical range. Taken together with the previously measured low abundance of lithium, the very low upper limits on Be and B suggest that BD+44 degrees 493 was formed at a very early time, and that it could well be a bona-fide second-generation star. Finally, the Pb upper limit strengthens the argument for non-s-process production of the heavy-element abundance patterns in CEMP-no stars.en_US
dc.description.sponsorshipPhysics Frontier Center/Joint Institute or Nuclear Astrophysics (JINA)en_US
dc.description.sponsorshipUS National Science Foundationen_US
dc.description.sponsorshipNSF CAREER AST-1255160en_US
dc.description.sponsorshipJSPS 23224004en_US
dc.description.sponsorshipNASA through a grant from the Space Telescope Science Institute GO-12554en_US
dc.description.sponsorshipAssociation of Universities for Research in Astronomy, Inc., under NASA NAS 5-26555en_US
dc.description.sponsorshipPHY 08-22648en_US
dc.identifier.citationPlacco, Vinicius, Timothy Beers, Ian Roederer, John Cowan, Anna Frebel, Dan Filler, Inese I. Ivans et al. "Hubble Space Telescope Near-Ultraviolet Spectroscopy of the Bright CEMP-no Star BD+ 44 493." arXiv preprint arXiv:1406.0538 (Jul., 2014).en_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.subjectgalaxy: haloen_US
dc.subjectstars: abundancesen_US
dc.subjectstars: atmospheresen_US
dc.subjectstars: individualen_US
dc.subject(bd+44 degrees 493)en_US
dc.subjectstars: population iien_US
dc.subjecttechniques: spectroscopicen_US
dc.subjectmetal-poor starsen_US
dc.subjectgiant branch starsen_US
dc.subjectneutron-capture elementsen_US
dc.subjectpopulation-iii supernovaeen_US
dc.subjectlow-metallicity starsen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleHubble Space Telescope Near-Ultraviolet Spectroscopy Of The Bright CEMP-No Star BD+44 Degrees 493en_US

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