Results 31 to 40 of about 158,293 (319)

An Elemental Assay of Very, Extremely, and Ultra Metal-Poor Stars [PDF]

, 2015
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), and 4 of which are ultra metal-poor (UMP; [Fe/H] < -4.0). These stars were
Asplund, M., Beers, T. C., Bessell, M. S., Christlieb, N., Frebel, A., Hansen, C. J., Hansen, T., Norris, J. E., Perez, A. E. Garcia, Placco, V. M., Yong, D.   +10 more
core   +2 more sources

On the Origins of Extreme Velocity Stars as Revealed by Large-scale Galactic Surveys

The Astronomical Journal, 2023
We assemble a large sample of 12,784 high-velocity stars with total velocity V _GSR ≥ 300 km s ^−1 , selected from RAVE DR5, SDSS DR12, LAMOST DR8, APOGEE DR16, GALAH DR2, and Gaia EDR3.
Qing-Zheng Li, Yang Huang, Xiao-Bo Dong, Hua-Wei Zhang, Timothy C. Beers, Zhen Yuan   +5 more
doaj   +1 more source

Influence of Population III stars on cosmic chemical evolution [PDF]

, 2009
New observations from the Hubble ultra deep field suggest that the star formation rate at z>7 drops off faster than previously thought. Using a newly determined star formation rate for the normal mode of Population II/I stars (PopII/I), including this ...
Aguirre, Alvarez, Aracil, Bagla, Barton, Beers, Beers, Bessell, Bessell, Bouwens, Bromm, Bromm, Bromm, Cayrel, Christlieb, Christlieb, Collet, D. Maurin, Daigne, Daigne, Daigne, Dunkley, E. Rollinde, E. Vangioni, Ekström, F. Daigne, F. H. Vincent, Fan, Faucher-Giguère, Frebel, Frebel, Frebel, Frebel, Frebel, Greif, Greif, Greif, Greiner, Heger, Heger, Henriques, Hopkins, Iye, J. Silk, Jenkins, Johnson, Johnson, Johnson, Johnson, K. A. Olive, Kampakoglou, Karlsson, Kawai, Kirby, Kneib, Komiya, Ledoux, Madau, Maeder, Mori, Nagao, Nomoto, Norris, Oesch, Press, Prochaska, Ryan, Salvadori, Santoro, Schaerer, Schoerck, Sheth, Shigeyama, Smith, Songaila, Spergel, Springel, Stiavelli, Suda, Tanvir, Tominaga, Trenti, Tsujimoto, Tumlinson, Tumlinson, van den Hoek, Venn, Wada, Woosley, Yoshida   +89 more
core   +1 more source

Metallicity Distribution Functions of 13 Ultra-faint Dwarf Galaxy Candidates from Hubble Space Telescope Narrowband Imaging

The Astrophysical Journal, 2023
We present uniformly measured stellar metallicities of 463 stars in 13 Milky Way (MW) ultra-faint dwarf galaxies (UFDs; M _V = −7.1 to −0.8) using narrowband CaHK (F395N) imaging taken with the Hubble Space Telescope.
Sal Wanying Fu, Daniel R. Weisz, Else Starkenburg, Nicolas Martin, Alessandro Savino, Michael Boylan-Kolchin, Patrick Côté, Andrew E. Dolphin, Alexander P. Ji, Nicolas Longeard, Mario L. Mateo, Ekta Patel, Nathan R. Sandford   +12 more
doaj   +1 more source

An overview of the rotational behavior of metal-poor stars [PDF]

Proceedings of the International Astronomical Union, 2009
AbstractWe describe the behavior of the rotational velocity in metal-poor stars ([Fe/H] ~ −0.5 dex) at different evolutionary stages, based on v sin i values from the literature. Our sample is composed of stars in the field and in some Galactic globular clusters, including stars on the main sequence (MS), red-giant branch (RGB), and horizontal branch ...
J. D. do Nascimento, J. R. P. Silva, Márcio Catelan, Márcio Catelan, Márcio Catelan, J. R. De Medeiros, Cristián E. Cortés, A. Recio-Blanco   +7 more
openaire   +11 more sources

GTC Follow-up Observations of Very Metal-poor Star Candidates from DESI

The Astrophysical Journal, 2023
The observations from the Dark Energy Spectroscopic Instrument (DESI) will significantly increase the numbers of known extremely metal-poor stars by a factor of ∼10, improving the sample statistics to study the early chemical evolution of the Milky Way ...
Carlos Allende Prieto, David S. Aguado, Jonay I. González Hernández, Rafael Rebolo, Joan Najita, Christopher J. Manser, Constance Rockosi, Zachary Slepian, Mar Mezcua, Monica Valluri, Rana Ezzeddine, Sergey E. Koposov, Andrew P. Cooper, Arjun Dey, Boris T. Gänsicke, Ting S. Li, Katia Cunha, Siwei Zou, Jessica Nicole Aguilar, Steven Ahlen, David Brooks, Todd Claybaugh, Shaun Cole, Sarah Eftekharzadeh, Kevin Fanning, Jaime Forero-Romero, Satya Gontcho A Gontcho, Klaus Honscheid, Pascale Jablonka, Robert Kehoe, Theodore Kisner, Martin Landriau, Axel de la Macorra, Aaron Meisner, Ramón Miquel, John Moustakas, Jundan Nie, Claire Poppett, Francisco Prada, Mehdi Rezaie, Graziano Rossi, Eusebio Sánchez, Michael Schubnell, Ray Sharples, Malgorzata Siudek, Verne V. Smith, Gregory Tarlé, Fiorenzo Vincenzo, Benjamin Alan Weaver, Zhimin Zhou, Hu Zou   +50 more
doaj   +1 more source

In the thick of it: metal-poor disc stars in RAVE [PDF]

Monthly Notices of the Royal Astronomical Society, 2013
Comment: 17 pages, 18 figures, accepted for publication in ...
Warren A. Reid, George M. Seabroke, Brad K. Gibson, Kenneth C. Freeman, Tomaž Zwitter, Olivier Bienaymé, Alessandro Siviero, Julio F. Navarro, Gerard Gilmore, Georges Kordopatis, Ulisse Munari, Paul J. McMillan, Quentin A. Parker, Quentin A. Parker, Matthias Steinmetz, Eva K. Grebel, Rosemary F. G. Wyse, Arnaud Siebert, Joss Bland-Hawthorn, Ivan Minchev, Corrado Boeche   +20 more
openaire   +6 more sources

Phase-space Properties and Chemistry of the Sagittarius Stellar Stream Down to the Extremely Metal-poor ([Fe/H] ≲ −3) Regime

The Astrophysical Journal, 2023
In this work, we study the phase-space and chemical properties of the Sagittarius (Sgr) stream, the tidal tails produced by the ongoing destruction of the Sgr dwarf spheroidal (dSph) galaxy, focusing on its very metal-poor (VMP; [Fe/H] < −2) content.
Guilherme Limberg, Anna B. A. Queiroz, Hélio D. Perottoni, Silvia Rossi, João A. S. Amarante, Rafael M. Santucci, Cristina Chiappini, Angeles Pérez-Villegas, Young Sun Lee   +8 more
doaj   +1 more source

Finding the First Stars: The Hamburg/ESO Objective Prism Survey [PDF]

, 1999
We report on a search for extremely metal-poor ([Fe/H]
Beers, T. C., Christlieb, N., Gehren, T., Reetz, J., Reimers, D., Wisotzki, L.   +5 more
core   +3 more sources

ABOUT THE HEAVY ELEMENTS ABUNDANCES IN THE ATMOSPHERES OF STARS WITH LOW METALLICITY

Odessa Astronomical Publications, 2017
We present results of preliminary determinations of abundances of heavy elements in three metal-poor stars: HD37828, HD44008, HD221170. Careful comparison of observed and synthetic spectra permit us to increase the number of lines heavy elements ...
V. F. Gopka, A. V. Yushchenko, T. V. Mishenina, V. V. Kovtyukh   +3 more
doaj   +1 more source