HUBBLE SPACE TELESCOPE NEAR-ULTRAVIOLET SPECTROSCOPY OF BRIGHT CEMP-s STARS
Name
Placco-2015-HUBBLE SPACE TELESCO.pdf
Size
2.22 MB
Format
Adobe PDF
Checksum (MD5)
67cc637190d100be5ccc9dc83ba5479f
Author(s)
Placco, Vinicius M.
Beers, Timothy C.
Ivans, Inese I.
Filler, Dan
Imig, Julie A.
Roederer, Ian U.
Abate, Carlo
Hansen, Terese
Cowan, John J.
Lawler, James E.
Date Issued
October 2015
Journal
The Astrophysical Journal
Publisher
IOP Publishing
Citation
Placco, Vinicius M., Timothy C. Beers, Inese I. Ivans, Dan Filler, Julie A. Imig, Ian U. Roederer, Carlo Abate, et al. “HUBBLE SPACE TELESCOPE NEAR-ULTRAVIOLET SPECTROSCOPY OF BRIGHT CEMP- s STARS.” The Astrophysical Journal 812, no. 2 (October 14, 2015): 109. © 2015 The American Astronomical Society
Version
Final published version
Abstract
We present an elemental-abundance analysis, in the near-ultraviolet (NUV) spectral range, for the bright carbon-enhanced metal-poor (CEMP) stars HD 196944 (V = 8.40, [Fe/H] = −2.41) and HD 201626 (V = 8.16, [Fe/H] = −1.51), based on data acquired with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope. Both of these stars belong to the sub-class CEMP-s, and exhibit clear over-abundances of heavy elements associated with production by the slow neutron-capture process. HD 196944 has been well-studied in the optical region, but we add abundance results for six species (Ge, Nb, Mo, Lu, Pt, and Au) that are only accessible in the NUV. In addition, we provide the first determination of its orbital period, P = 1325 days. HD 201626 has only a limited number of abundance results based on previous optical work—here we add five new species from the NUV, including Pb. We compare these results with models of binary-system evolution and s-process element production in stars on the asymptotic giant branch, with the goal of explaining their origin and evolution. Our best-fitting models for HD 196944 (M[subscript 1,i] = 0.9M[subscript ʘ], M[subscript 2,i] = 0.86M[subscript ʘ], for [Fe/H] = -2.2), and HD 201626 (M[subscript 1,i] = 0.9M[subscript ʘ], M[subscript 2,i] = 0.76M[subscript ʘ], for [Fe/H] = -2.2; M[subscript 1,i] = 1.6M[subscript ʘ], M[subscript 2,i] = 0.59M[subscript ʘ], for [Fe/H] = -1.5) are consistent with the current accepted scenario for the formation of CEMP-s stars.
MIT Department
Massachusetts Institute of Technology. Department of Physics
MIT Kavli Institute for Astrophysics and Space Research
Terms of Use
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.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1088/0004-637x/812/2/109
