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Heavy-Element Dispersion In The Metal-Poor Globular Cluster M92
(2011-07)
Dispersion among the light elements is common in globular clusters (GCs), while dispersion among heavier elements is less common. We present detection of r-process dispersion relative to Fe in 19 red giants of the metal-poor ...
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 ...
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 ...
Hubble Space Telescope Near-Ultraviolet Spectroscopy Of The Bright CEMP-No Star BD+44 Degrees 493
(2014-07)
We 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 ...
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 Two Metallicity Groups Of The Globular Cluster M22: A Chemical Perspective
(2011-08)
We present a detailed chemical composition analysis of 35 red giant stars in the globular cluster M22. High resolution spectra for this study were obtained at five observatories, and analyzed in a uniform manner. We have ...
Characterizing The Heavy Elements In Globular Cluster M22 And An Empirical S-Process Abundance Distribution Derived From The Two Stellar Groups
(2011-11)
We present an empirical s-process abundance distribution derived with explicit knowledge of the r-process component in the low-metallicity globular cluster M22. We have obtained high-resolution, high signal-to-noise spectra ...
New Detections Of Arsenic, Selenium, And Other Heavy Elements In Two Metal-Poor Stars
(2014-08)
We use the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope to obtain new high-quality spectra covering the 1900 <= lambda <= 2360 angstrom wavelength range for two metal-poor stars, HD 108317 and ...
The Two Metallicity Groups Of The Globular Cluster M22: A Chemical Perspective
(2011-08)
We present a detailed chemical composition analysis of 35 red giant stars in the globular cluster M22. High resolution spectra for this study were obtained at five observatories, and analyzed in a uniform manner. We have ...
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 ...