5.4k citations · 64.6k across the 531 of their papers we have counts for
16 papers · 2 filters
Metallicity estimates for A-, F-, and G-type stars from the Edinburgh-Cape blue object survey
T. C. Beers, S. Rossi, D. O'Donoghue +4
The Edinburgh-Cape Blue Object Survey is an ongoing project to identify and analyse a large sample of hot stars selected initially on the basis of photographic colours (down to a m…
Structure of the Galactic Stellar Halo Prior to Disk Formation
Masashi Chiba, Timothy C. Beers
We develop a method for recovering the global density distribution of the ancient Galactic stellar halo prior to disk formation, based on the present orbits of metal-poor stars obs…
Ultra-Lithium-Deficient Halo Stars and Blue Stragglers: A Common Origin?
Sean G. Ryan, Timothy C. Beers, Toshitaka Kajino +1
We present data for four ultra-Li-deficient, warm, halo stars. The Li deficiency of two of these is a new discovery. Three of the four stars have effective temperatures Teff ~ 6300…
Abundances and Evolution of Lithium in the Galactic Halo and Disk
Sean G. Ryan, Toshitaka Kajino, Timothy C. Beers +4
We have measured the Li abundance of 18 stars with -2 <~ [Fe/H] ~< -1 and 6000 K <~ Teff <~ 6400 K, a parameter range that was poorly represented in previous studies. We examine th…
s- and r-process elements in two very metal-poor stars
Sean G. Ryan, Wako Aoki, Lisa A. J. Blake +5
New measurements of neutron-capture elements are presented for two very metal-poor stars ([Fe/H] ~ -3). One (LP 625-44) has an s-process signature believed to be due to mass transf…
A Search for Stars of Very Low Metal Abundance. V. Photoelectric UBV Photometry of Metal-Weak Candidates from the Northern HK Survey
P. Bonifacio, S. Monai, T. C. Beers
We report photoelectric UBV data for 268 metal-poor candidates chosen from the northern HK objective-prism/interference-filter survey of Beers and colleagues. Over 40 % of the star…
The INT Search for Metal-Poor Stars. Spectroscopic Observations and Classification via Artificial Neural Networks
C. Allende Prieto, R. Rebolo, R. J. Garcia Lopez +5
With the dual aims of enlarging the list of extremely metal-poor stars identified in the Galaxy, and boosting the numbers of moderately metal-deficient stars in directions that sam…
Detection of Lead in the Carbon-Rich, Very Metal-Poor Star LP625-44: A Strong Constraint on s-Process Nucleosynthesis at Low Metallicity
W. Aoki, J. E. Norris, S. G. Ryan +2
We report the detection of the Pb I 4057.8A line in the very metal-poor ([Fe/H]=-2.7), carbon-rich star, LP625-44. We determine the abundance of Pb ([Pb/Fe] = 2.65) and 15 other ne…
Extremely Metal-Poor Stars. VII. The Most Metal-Poor Dwarf, CS 22876-032
John E. Norris, Timothy C. Beers, Sean G. Ryan
We report high-resolution, high-signal-to-noise, observations of the extremely metal-poor double-lined spectroscopic binary CS 22876-032. The system has a long period : P = 424.7 $…
Primordial Lithium Abundance as a Stringent Constraint on the Baryonic Content of the Universe
Takeru Ken Suzuki, Yuzuru Yoshii, Timothy C. Beers
We have refined the estimate of the primordial level of Li abundance to an accuracy better than 10%, based on high-precision Li abundances for metal-poor halo stars, and a rece…
A Search for Stars of Very Low Metal Abundance. IV. uvbyCa Observations of Metal-Weak Candidates from the Northern HK Survey
Barbara J. Anthony-Twarog, Ata Sarajedini, Timothy C. Beers +1
CCD photometry on the uvbyCa system has been obtained for 521 candidate metal-poor stars from the northern hemisphere HK survey of Beers and colleagues. Reddening corrections, clas…
Kinematics of Metal-Poor Stars in the Galaxy. II. Proper Motions for a Large Non-Kinematically Selected Sample
T. C. Beers, M. Chiba, Y. Yoshii +4
We present a revised catalog of 2106 Galactic stars, selected without kinematic bias, and with available radial velocities, distance estimates, and metal abundances in the range 0.…
Kinematics of Metal-Poor Stars in the Galaxy. III. Formation of the Stellar Halo and Thick Disk as Revealed from a Large Sample of Non-Kinematically Selected Stars
M. Chiba, T. C. Beers
(Abbreviated) We present a detailed analysis of the space motions of 1203 solar-neighborhood stars with metal abundances [Fe/H] <= -0.6, on the basis of a recently revised and supp…
Evidence of Multiple r-Process Sites in the Early Galaxy: New Observations of CS 22892-052
Christopher Sneden, John J. Cowan, Inese I. Ivans +4
First results are reported of a new abundance study of neutron-capture elements in the ultra-metal-poor (UMP; [Fe/H] = -3.1) halo field giant star CS 22892-052. Using new high reso…
The Light Elements Be and B as Stellar Chronometers in the Early Galaxy
Timothy C. Beers, Takeru K. Suzuki, Yuzuru Yoshii
Recent detailed simulations of Galactic Chemical Evolution have shown that the heavy elements, in particular [Fe/H], are expected to exhibit a weak, or absent, correlation with ste…
Ongoing Large Surveys for Metal-Poor Stars in the Galactic Halo
Norbert Christlieb, Timothy C. Beers
We report on two major surveys for metal-poor stars in the galactic halo, the HK survey, and the Hamburg/ESO survey, which have been undertaken in order to provide targets for high…