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Improved V II Log(gf) Values, Hyperfine Structure Constants, and Abundance Determinations in the Photospheres of the Sun and Metal-Poor Star HD 84937
(2014-10)
New experimental absolute atomic transition probabilities are reported for 203 lines of VII. Branching fractions are measured from spectra recorded using a Fourier transform spectrometer and an echelle spectrometer. The ...
Chemical Compositions Of Thin-Disk, High-Metallicity Red Horizontal-Branch Field Stars
(2012-07)
We present a detailed abundance analysis and atmospheric parameters of 76 stars from a survey to identify field Galactic red horizontal-branch (RHB) stars. High-resolution echelle spectra (R similar or equal to 60,000, S/N ...
The Chemical Compositions Of RR Lyrae Type C Variable Stars
(2014-02)
We present a detailed chemical abundance study of eight RR Lyrae variable stars of subclass c (RRc). The target RRc stars chosen for study exhibit "Blazhko-effect" period and amplitude modulations to their pulsational ...
Improved Ni I Log(gf) Values and Abundance Determinations in the Photospheres of the Sun and Metal-Poor Star HD 84937
(2014-04)
Atomic transition probability measurements for 371 Ni I lines in the UV through near-IR are reported. Branching fractions from data recorded using a Fourier transform spectrometer and a new echelle spectrograph are combined ...
Improved V I Log(gf) Values and Abundance Determinations in the Photospheres of the Sun and Metal-Poor Star HD 84937
(2014-12)
New emission branching fraction measurements for 836 lines of the first spectrum of vanadium (V I) are determined from hollow cathode lamp spectra recorded with the National Solar Observatory 1 m Fourier transform spectrometer ...
Neutron-Capture Nucleosynthesis In The First Stars*
(2014-04)
Recent studies suggest that metal-poor stars enhanced in carbon but containing low levels of neutron-capture elements may have been among the first to incorporate the nucleosynthesis products of the first generation of ...
The Chemical Abundances Of Stars In The Halo (CASH) Project. II. A Sample Of 14 Extremely Metal-Poor Stars
(2011-11)
We present a comprehensive abundance analysis of 20 elements for 16 new low-metallicity stars from the Chemical Abundances of Stars in the Halo (CASH) project. The abundances have been derived from both Hobby-Eberly Telescope ...
New Hubble Space Telescope Observations of Heavy Elements in Four Metal-Poor Stars
(2012-12)
Elements heavier than the iron group are found in nearly all halo stars. A substantial number of these elements, key to understanding neutron-capture nucleosynthesis mechanisms, can only be detected in the near-ultraviolet. ...
First Stars XVI. HST/STIS Abundances Of Heavy Elements In The Uranium-Rich Metal-Poor Star CS 31082-001
(2013-02)
Context. The origin and site(s) of the r-process nucleosynthesis is(are) still not known with certainty, but complete, detailed r-element abundances off er our best clues. The few extremely metal-poor (EMP) stars with large ...
A Detailed Study Of Giants And Horizontal Branch Stars In M68: Atmospheric Parameters And Chemical Abundances
(2015-06)
In this paper, we present a detailed high-resolution spectroscopic study of post main sequence stars in the globular cluster (GC) M68. Our sample, which covers a range of 4000K in T-eff, and 3.5 dex in log(g), is comprised ...