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New Rare Earth Element Abundance Distributions for the Sun and Five R-Process-Rich Very Metal-Poor Stars
(2009-05)
We have derived new abundances of the rare earth elements Pr, Dy, Tm, Yb, and Lu for the solar photosphere and for five very metal-poor, neutron-capture r-process-rich giant stars. The photospheric values for all five ...
Multi-Element Abundance Measurements From Medium-Resolution Spectra. I. The Sculptor Dwarf Spheroidal Galaxy
(2009-11)
We present measurements of Fe, Mg, Si, Ca, and Ti abundances for 388 radial velocity member stars in the Sculptor dwarf spheroidal galaxy (dSph), a satellite of the Milky Way (MW). This is the largest sample of individual ...
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 Co I Log(gf) Values and Abundance Determinations in the Photospheres of the Sun and Metal-Poor Star HD 84937
(2015-09)
New emission branching fraction measurements for 898 lines of the first spectrum of cobalt (Co I) are determined from hollow cathode lamp spectra recorded with the National Solar Observatory 1 m Fourier transform spectrometer ...
Detection of the Second r-Process Peak Element Tellurium in Metal-Poor Stars
(2012-03)
Using near-ultraviolet spectra obtained with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope, we detect neutral tellurium in three metal-poor stars enriched by products of r-process nucleosynthesis, ...
Improved Laboratory Transition Probabilities for Ce II, Application to the Cerium Abundances of the Sun and Five R-Process-Rich, Metal-Poor Stars, and Rare Earth Lab Data Summary
(2009-05)
Recent radiative lifetime measurements accurate to +/- 5% using laser-induced fluorescence (LIF) on 43 even-parity and 15 odd-parity levels of Ce II have been combined with new branching fractions measured using a Fourier ...
The Abundances Of Neutron-Capture Species In The Very Metal-Poor Globular Cluster M15: A Uniform Analysis Of Red Giant Branch And Red Horizontal Branch Stars
(2011-06)
The globular cluster M15 is unique in its display of star-to-star variations in the neutron-capture elements. Comprehensive abundance surveys have been previously conducted for handfuls of M15 red giant branch (RGB) and ...
Metallicity And Alpha-Element Abundance Measurement In Red Giant Stars From Medium-Resolution Spectra
(2008-08)
We present a technique that applies spectral synthesis to medium-resolution spectroscopy (MRS; R similar to 6000) in the red (6300 angstrom < lambda < 9100 angstrom) to measure [Fe/H] and [alpha/Fe] of individual red giant ...
CS 22964-161: A Double-Lined Carbon- And S-Process-Enhanced Metal-Poor Binary Star
(2008-04)
A detailed high-resolution spectroscopic analysis is presented for the carbon-rich low-metallicity Galactic halo object CS 22964-161. We have discovered that CS 22964-161 is a double-lined spectroscopic binary and have ...
Improved Ti II Log(gf) Values and Abundance Determinations in the Photospheres of the Sun and Metal-Poor Star HD 84937
(2013-10)
Atomic transition probability measurements for 364 lines of Ti II in the UV through near-IR are reported. Branching fractions from data recorded using a Fourier transform spectrometer (FTS) and a new echelle spectrometer ...