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Chemical signatures of planetary systems in their host stars. Near-infrared spectroscopy of four planet-hosting wide binaries
Dongwook Lim, Sol Yun, Andreas J. Koch-Hansen +3
An important open question in exoplanet studies is whether planets leave detectable chemical fingerprints on their host stars. While several studies have suggested possible planeta…
J-PLUS: Beyond Spectroscopy III. Stellar Parameters and Elemental-abundance Ratios for Five Million Stars from DR3
Yang Huang, Timothy C. Beers, Kai Xiao +24
We present a catalog of stellar parameters (effective temperature , surface gravity , age, and metallicity [Fe/H]) and elemental-abundance ratios ([C/Fe], [Mg/…
SPLUSJ210428.01-004934.2: An Ultra Metal-Poor Star Identified from Narrowband Photometry
Vinicius M. Placco, Ian U. Roederer, Young Sun Lee +6
We report on the discovery of SPLUS J210428.01-004934.2, an ultra metal-poor (UMP) star first identified from the narrow-band photometry of the Southern Photometric Local Universe…
The R-Process Alliance: Spectroscopic Follow-up of Low-Metallicity Star Candidates from the Best & Brightest Survey
Vinicius M. Placco, Rafael M. Santucci, Timothy C. Beers +17
We present results from an observing campaign to identify low-metallicity stars in the Best & Brightest Survey. From medium-resolution (R ~ 1, 200 - 2, 000) spectroscopy of 857 can…
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…
Seven New Carbon-Enhanced Metal-Poor RR Lyrae Stars
Catherine R. Kennedy, Richard J. Stancliffe, Charles Kuehn +6
We report estimated carbon-abundance ratios, [C/Fe], for seven newly-discovered carbon-enhanced metal-poor (CEMP) RR Lyrae stars. These are well-studied RRab stars that had previou…
Metal-Poor Stars Observed with the Magellan Telescope II. Discovery of Four Stars with [Fe/H] < -3.5
Vinicius M. Placco, Anna Frebel, Timothy C. Beers +5
We report on the discovery of seven low-metallicity stars selected from the Hamburg/ESO Survey, six of which are extremely metal-poor ([Fe/H]<-3.0), with four having [Fe/H]<-3.5. C…
Carbon-enhanced Metal-poor Stars in SDSS/SEGUE. II. Comparison of CEMP Star Frequencies with Binary Population Synthesis Models
Young Sun Lee, Takuma Suda, Timothy C. Beers +1
We present a comparison of the frequencies of carbon-enhanced metal-poor (CEMP) giant and main-sequence turnoff stars, selected from the Sloan Digital Sky Survey and the Sloan Exte…
Carbon-enhanced Metal-poor Stars in SDSS/SEGUE. I. Carbon Abundance Estimation and Frequency of CEMP Stars
Young Sun Lee, Timothy C. Beers, Thomas Masseron +8
We describe a method for the determination of stellar [C/Fe] abundance ratios using low-resolution (R = 2000) stellar spectra from the SDSS and SEGUE. By means of a star-by-star co…
High-Resolution Spectroscopy of Extremely Metal-Poor Stars from SDSS/SEGUE: I. Atmospheric Parameters and Chemical Compositions
Wako Aoki, Timothy C. Beers, Young Sun Lee +8
Chemical compositions are determined based on high-resolution spectroscopy for 137 candidate extremely metal-poor (EMP) stars selected from the Sloan Digital Sky Survey (SDSS) and…
The Metallicity Distribution Functions of SEGUE G and K dwarfs: Constraints for Disk Chemical Evolution and Formation
Katharine J. Schlesinger, Jennifer A. Johnson, Constance M. Rockosi +14
We present the metallicity distribution function (MDF) for 24,270 G and 16,847 K dwarfs at distances from 0.2 to 2.3 kpc from the Galactic plane, based on spectroscopy from the Slo…
Searches for Metal-Poor Stars from the Hamburg/ESO Survey using the CH G-band
Vinicius M. Placco, Catherine R. Kennedy, Timothy C. Beers +6
We describe a new method to search for metal-poor candidates from the Hamburg/ESO objective-prism survey (HES) based on identifying stars with apparently strong CH G-band strengths…
[O/Fe] Estimates for Carbon-Enhanced Metal-Poor Stars from Near-IR Spectroscopy
Catherine R. Kennedy, Thirupathi Sivarani, Timothy C. Beers +6
We report on oxygen abundances determined from medium-resolution near-IR spectroscopy for a sample of 57 carbon-enhanced metal-poor (CEMP) stars selected from the Hamburg/ESO surve…
Binary Contamination in the SEGUE sample: Effects on SSPP Determinations of Stellar Atmospheric Parameters
Katharine J. Schlesinger, Jennifer A. Johnson, Young Sun Lee +5
Using numerical modeling and a grid of synthetic spectra, we examine the effects that unresolved binaries have on the determination of various stellar atmospheric parameters for SE…
A Search for Unrecognized Carbon-Enhanced Metal-Poor Stars in the Galaxy
Vinicius M. Placco, Catherine R. Kennedy, Silvia Rossi +6
We have developed a new procedure to search for carbon-enhanced metal-poor (CEMP) stars from the Hamburg/ESO (HES) prism-survey plates. This method employs an extended line index f…