490 citations · 5.9k across the 130 of their papers we have counts for
7 papers · 1 filter
Are There Any Stars Lacking Neutron-Capture Elements? Evidence from Strontium and Barium
Ian U. Roederer
The cosmic dispersion in the abundances of the heavy elements strontium and barium in halo stars is well known. Strontium and barium are detected in most cool, metal-poor giants, b…
New Hubble Space Telescope Observations of Heavy Elements in Four Metal-Poor Stars
Ian U. Roederer, James E. Lawler, Jennifer S. Sobeck +7
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, ca…
Germanium, Arsenic, and Selenium Abundances in Metal-Poor Stars
Ian U. Roederer
The elements germanium (Ge, Z=32), arsenic (As, Z=33), and selenium (Se, Z=34) span the transition from charged-particle or explosive synthesis of the iron-group elements to neutro…
Detection of Elements at All Three r-process Peaks in the Metal-Poor Star HD 160617
Ian U. Roederer, James E. Lawler
We report the first detection of elements at all three r-process peaks in the metal-poor halo star HD 160617. These elements include arsenic and selenium, which have not been detec…
RR-Lyrae-type pulsations from a 0.26-solar-mass star in a binary system
G. Pietrzynski, I. B. Thompson, W. Gieren +14
RR Lyrae pulsating stars have been extensively used as tracers of old stellar populations for the purpose of determining the ages of galaxies, and as tools to measure distances to…
The double sub-giant branch of NGC 6656 (M22): a chemical characterization
A. F. Marino, A. P. Milone, C. Sneden +14
We present an abundance analysis of 101 subgiant branch (SGB) stars in the globular cluster M22. Using low resolution FLAMES/GIRAFFE spectra we have determined abundances of the ne…