1k citations · 5.2k across the 51 of their papers we have counts for
52 papers
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…
Substructures of the Milky Way's Retrograde Halo: Evidence for Multiple Accretion Events
Young Kwang Kim, Young Sun Lee, Timothy C. Beers
We investigate the progenitors of low-inclination retrograde substructures in the Milky Way (MW) halo, which are remnants of accreted dwarf galaxies on retrograde orbits. Our sampl…
Carbon-Enhanced Metal-Poor Star Candidates in the Milky Way from J-PLUS and S-PLUS
Jihye Hong, Timothy C. Beers, Yang Huang +4
Recent large-scale multi-band photometric surveys now enable elemental-abundance estimates for millions of stars with accuracies approaching those of low- to medium-resolution spec…
Deciphering the Milky Way's star formation at cosmic noon with high proper-motion stars: A precursor to the merger-driven starburst
Deokkeun An, Young Sun Lee, Yutaka Hirai +1
Evidence suggests that the Milky Way (MW) underwent a major collision with the Gaia-Sausage/Enceladus (GSE) dwarf galaxy around cosmic noon. While GSE has since been fully disrupte…
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/…
Candidate Members of the VMP/EMP Disk System of the Galaxy from the SkyMapper and SAGES Surveys
Jihye Hong, Timothy C. Beers, Young Sun Lee +15
Photometric stellar surveys now cover a large fraction of the sky, probe to fainter magnitudes than large-scale spectroscopic surveys, and are relatively free from the target-selec…
Probing the Galactic Halo with RR Lyrae Stars -- V. Chemistry, Kinematics, and Dynamically Tagged Groups
Jonathan Cabrera Garcia, Timothy C. Beers, Yang Huang +9
We employ a sample of 135,873 RR Lyrae stars (RRLs) with precise photometric-metallicity and distance estimates from the newly calibrated ------[Fe/H] and …
Diverse Chemo-Dynamical Properties of Nitrogen-Rich Stars Identified From Low-Resolution Spectra
Changmin Kim, Young Sun Lee, Timothy C. Beers +1
The second generation of stars in the GCs of the MW exhibit unusually high N, Na, or Al, compared to typical Galactic halo stars at similar metallicities. The halo field stars enha…
A Blueprint for the Milky Way's Stellar Populations. IV. A String of Pearls the Galactic Starburst Sequence
Deokkeun An, Timothy C. Beers, Young Sun Lee +1
We continue our series of papers on phase-space distributions of stars in the Milky Way based on photometrically derived metallicities and Gaia astrometry, with a focus on the halo…
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…
Evidence For Multiple Accretion Events in the -Sausage/Enceladus Structures
Young Kwang Kim, Young Sun Lee, Timothy C. Beers +1
We present evidence that multiple accretion events are required to explain the origin of the -Sausage and Enceladus (GSE) structures, based on an analysis of dynamical proper…
Origin and Status of Low-Mass Candidate Hypervelocity Stars
Bum-Suk Yeom, Young Sun Lee, Jae-Rim Koo +2
We present an analysis of the chemical abundances and kinematics of six low-mass dwarf stars, previously claimed to be candidate hypervelocity stars (HVSs). We obtained moderate-re…
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…
Carbon in Red Giants in Globular Clusters and Dwarf Spheroidal Galaxies
Evan N. Kirby, Michelle Guo, Andrew J. Zhang +6
We present carbon abundances of red giants in Milky Way globular clusters and dwarf spheroidal galaxies (dSphs). Our sample includes measurements of carbon abundances for 154 giant…
The Vertical Metallicity Gradient of the Milky Way Disk: Transitions in [a/Fe] Populations
Katharine J. Schlesinger, Jennifer A. Johnson, Constance M. Rockosi +10
Using G dwarfs from the Sloan Extension for Galactic Understanding and Exploration (SEGUE) survey, we have determined a vertical metallicity gradient over a large volume of the Mil…
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…
Possible Evidence for Metal Accretion onto the Surfaces of Metal-Poor Main-Sequence Stars
Kohei Hattori, Yuzuru Yoshii, Timothy C. Beers +2
The entire evolution of the Milky Way, including its mass-assembly and star-formation history, is imprinted onto the chemo-dynamical distribution function of its member stars, f(x,…
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…
Chemical Cartography with APOGEE: Large-scale Mean Metallicity Maps of the Milky Way
Michael R. Hayden, Jon A. Holtzman, Jo Bovy +27
We present Galactic mean metallicity maps derived from the first year of the SDSS-III APOGEE experiment. Mean abundances in different zones of Galactocentric radius (0 < R < 15 kpc…
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…
Hypervelocity Star Candidates in the SEGUE G & K Dwarf Sample
Lauren E. Palladino, Katharine J. Schlesinger, Kelly Holley-Bockelmann +4
We present 20 candidate hypervelocity stars from the Sloan Extension for Galactic Understanding and Exploration (SEGUE) G and K dwarf samples. Previous searches for hypervelocity s…
The Tenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Apache Point Observatory Galactic Evolution Experiment
Christopher P. Ahn, Rachael Alexandroff, Carlos Allende Prieto +232
The Sloan Digital Sky Survey (SDSS) has been in operation since 2000 April. This paper presents the tenth public data release (DR10) from its current incarnation, SDSS-III. This da…