342 citations · 6.5k across the 144 of their papers we have counts for
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The role of binaries in the enrichment of the early Galactic halo. II. Carbon-Enhanced Metal-Poor Stars - CEMP-no stars
T. T. Hansen, J. Andersen, B. Nordström +4
The detailed composition of most metal-poor halo stars has been found to be very uniform. However, a fraction of 20-70% (increasing with decreasing metallicity) exhibit dramatic en…
Abundances of carbon-enhanced metal-poor stars as constraints on their formation
C. J. Hansen, B. Nordstroem, T. T. Hansen +6
An increasing fraction of carbon-enhanced metal-poor (CEMP) stars is found as their iron abundance, [Fe/H], decreases below [Fe/H] = -2.0. The CEMP-s stars have the highest absolut…
Chronography of the Milky Way's Halo System with Field Blue Horizontal-Branch Stars
R. M. Santucci, T. C. Beers, V. M. Placco +6
In a pioneering effort, Preston et al. reported that the colors of blue horizontal-branch (BHB) stars in the halo of the Galaxy shift with distance, from regions near the Galactic…
The Fractions of Inner- and Outer-Halo Stars in the Local Volume
Deokkeun An, Timothy C. Beers, Rafael M. Santucci +4
We obtain a new determination of the metallicity distribution function (MDF) of stars within - kpc of the Sun, based on recently improved co-adds of photometry f…
The Chemical Abundances of Stars in the Halo (CASH) Project. III. A New Classification Scheme for Carbon-Enhanced Metal-poor Stars with S-process Element Enhancement
Julie K. Hollek, Anna Frebel, Vinicius M. Placco +4
We present a detailed abundance analysis of 23 elements for a newly discovered carbon-enhanced metal-poor (CEMP) star, HE 0414-0343, from the Chemical Abundances of Stars in the Ha…
Hubble Space Telescope Near-Ultraviolet Spectroscopy of Bright CEMP-s Stars
Vinicius M. Placco, Timothy C. Beers, Inese I. Ivans +14
We present an elemental-abundance analysis, in the near-ultraviolet (NUV) spectral range, for the bright carbon-enhanced metal-poor (CEMP) stars HD196944 (V = 8.40, [Fe/H] = -2.41)…
SD 1313-0019 -- Another second-generation star with [Fe/H] = -5.0, observed with the Magellan Telescope
Anna Frebel, Anirudh Chiti, Alexander P. Ji +2
We present a Magellan/MIKE high-resolution (R ~ 35,000) spectrum of the ancient star SD 1313-0019 which has an iron abundance of [Fe/H] = -5.0, paired with a carbon enhancement of…
Metal-Poor Stars Observed with the Magellan Telescope. III. New Extremely and Ultra Metal-Poor Stars from SDSS/SEGUE and Insights on the Formation of Ultra Metal-Poor Stars
Vinicius M. Placco, Anna Frebel, Young Sun Lee +5
We report the discovery of one extremely metal-poor (EMP; [Fe/H]<-3) and one ultra metal-poor (UMP; [Fe/H]<-4) star selected from the SDSS/SEGUE survey. These stars were identified…
An Elemental Assay of Very, Extremely, and Ultra Metal-Poor Stars
T. Hansen, C. J. Hansen, N. Christlieb +8
We present a high-resolution elemental-abundance analysis for a sample of 23 very metal-poor (VMP; [Fe/H] < -2.0) stars, 12 of which are extremely metal-poor (EMP; [Fe/H] < -3.0),…
The Frequency of Field Blue-Straggler Stars in the Thick Disk and Halo System of the Galaxy
Rafael M. Santucci, Vinicius M. Placco, Silvia Rossi +5
We present an analysis of a new, large sample of field blue-straggler stars (BSSs) in the thick disk and halo system of the Galaxy, based on stellar spectra obtained during the Slo…