HUBBLE SPACE TELESCOPE NEAR-ULTRAVIOLET SPECTROSCOPY OF THE BRIGHT CEMP-NO STAR BD+44°493
We present an elemental-abundance analysis, in the near-ultraviolet (NUV) spectral range, for the extremely metal-poor star BD+44°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....
| Main Authors: | , , , , , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
IOP Publishing
2015
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| Online Access: | http://hdl.handle.net/1721.1/93127 https://orcid.org/0000-0002-2139-7145 |
| _version_ | 1811082205706846208 |
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| author | Placco, Vinicius M. Beers, Timothy C. Roederer, Ian U. Cowan, John J. Filler, Dan Ivans, Inese I. Lawler, James E. Schatz, Hendrik Sneden, Christopher Sobeck, Jennifer S. Aoki, Wako Smith, Verne V. Frebel, Anna L. |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Placco, Vinicius M. Beers, Timothy C. Roederer, Ian U. Cowan, John J. Filler, Dan Ivans, Inese I. Lawler, James E. Schatz, Hendrik Sneden, Christopher Sobeck, Jennifer S. Aoki, Wako Smith, Verne V. Frebel, Anna L. |
| author_sort | Placco, Vinicius M. |
| collection | MIT |
| description | We present an elemental-abundance analysis, in the near-ultraviolet (NUV) spectral range, for the extremely metal-poor star BD+44°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°493, log ε (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 ε (Be) <–2.3, and lead, log ε (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°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. |
| first_indexed | 2024-09-23T11:59:22Z |
| format | Article |
| id | mit-1721.1/93127 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T11:59:22Z |
| publishDate | 2015 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/931272022-09-27T23:15:13Z HUBBLE SPACE TELESCOPE NEAR-ULTRAVIOLET SPECTROSCOPY OF THE BRIGHT CEMP-NO STAR BD+44°493 Placco, Vinicius M. Beers, Timothy C. Roederer, Ian U. Cowan, John J. Filler, Dan Ivans, Inese I. Lawler, James E. Schatz, Hendrik Sneden, Christopher Sobeck, Jennifer S. Aoki, Wako Smith, Verne V. Frebel, Anna L. Massachusetts Institute of Technology. Department of Physics Frebel, Anna L. We present an elemental-abundance analysis, in the near-ultraviolet (NUV) spectral range, for the extremely metal-poor star BD+44°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°493, log ε (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 ε (Be) <–2.3, and lead, log ε (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°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. National Science Foundation (U.S.) (CAREER Grant AST-1255160) 2015-01-22T16:43:00Z 2015-01-22T16:43:00Z 2014-06 2014-04 Article http://purl.org/eprint/type/JournalArticle 0004-637X 1538-4357 http://hdl.handle.net/1721.1/93127 Placco, Vinicius M., Timothy C. Beers, Ian U. Roederer, John J. 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.” The Astrophysical Journal 790, no. 1 (June 30, 2014): 34. © 2014 The American Astronomical Society https://orcid.org/0000-0002-2139-7145 en_US http://dx.doi.org/10.1088/0004-637X/790/1/34 The Astrophysical Journal Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf IOP Publishing American Astronomical Society |
| spellingShingle | Placco, Vinicius M. Beers, Timothy C. Roederer, Ian U. Cowan, John J. Filler, Dan Ivans, Inese I. Lawler, James E. Schatz, Hendrik Sneden, Christopher Sobeck, Jennifer S. Aoki, Wako Smith, Verne V. Frebel, Anna L. HUBBLE SPACE TELESCOPE NEAR-ULTRAVIOLET SPECTROSCOPY OF THE BRIGHT CEMP-NO STAR BD+44°493 |
| title | HUBBLE SPACE TELESCOPE NEAR-ULTRAVIOLET SPECTROSCOPY OF THE BRIGHT CEMP-NO STAR BD+44°493 |
| title_full | HUBBLE SPACE TELESCOPE NEAR-ULTRAVIOLET SPECTROSCOPY OF THE BRIGHT CEMP-NO STAR BD+44°493 |
| title_fullStr | HUBBLE SPACE TELESCOPE NEAR-ULTRAVIOLET SPECTROSCOPY OF THE BRIGHT CEMP-NO STAR BD+44°493 |
| title_full_unstemmed | HUBBLE SPACE TELESCOPE NEAR-ULTRAVIOLET SPECTROSCOPY OF THE BRIGHT CEMP-NO STAR BD+44°493 |
| title_short | HUBBLE SPACE TELESCOPE NEAR-ULTRAVIOLET SPECTROSCOPY OF THE BRIGHT CEMP-NO STAR BD+44°493 |
| title_sort | hubble space telescope near ultraviolet spectroscopy of the bright cemp no star bd 44°493 |
| url | http://hdl.handle.net/1721.1/93127 https://orcid.org/0000-0002-2139-7145 |
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