Now showing items 1-5 of 5

    • Dynamically Tagged Groups of Very Metal-poor Halo Stars from the HK and Hamburg/ESO Surveys 

      Limberg, Guilherme; Rossi, Silvia; Beers, Timothy; Perottoni, Helio; Perez-Villegas, Angeles; Santucci, Rafael; Abuchaim, Yuri; Placco, Vinicius; Lee, Young Sun; Christlieb, Norbert; Norris, John; Bessell, Michael; Ryan, Sean; Wilhelm, Ronald; Rhee, Jaehyon; Frebel, Anna (2021-01-20)
      We analyze the dynamical properties of ∼1500 very metal-poor (VMP; [Fe/H] ≲−2.0) halo stars, based primarily on medium-resolution spectroscopic data from the HK and Hamburg/ESO surveys. These data, collected over the past ...
    • The Most Metal-poor Stars. I : Discovery, Data and Atmospheric Parameters 

      Norris, John; Bessell, Michael; Yong, David; Christlieb, Norbert; Barklem, Paul; Asplund, Martin; Murphy, Michael; Beers, Timothy; Frebel, Anna; Ryan, Sean G. (2013-01)
      We report the discovery of 34 stars in the Hamburg/ESO Survey for metal-poor stars and the Sloan Digital Sky Survey that have [Fe/H] <~ -3.0. Their median and minimum abundances are [Fe/H] = -3.1 and -4.1, respectively, ...
    • The Most Metal-poor Stars. II : Chemical Abundances of 190 Metal-poor Stars Including 10 New Stars with [Fe/H] <= -3.5 

      Yong, David; Norris, John; Bessell, Michael S.; Asplund, Martin; Beers, Timothy C.; Barklem, Paul S.; Frebel, Anna; Ryan, Sean G. (2013-01)
      We present a homogeneous chemical abundance analysis of 16 elements in 190 metal-poor Galactic halo stars (38 program and 152 literature objects). The sample includes 171 stars with [Fe/H] <= -2.5, of which 86 are extremely ...
    • The Most Metal-poor Stars. III : The Metallicity Distribution Function and Carbon-enhanced Metal-poor Fraction 

      Yong, David; Norris, John; Bessell, Michael; Christlieb, Norbert; Asplund, Martin; Beers, Timothy; Barklem, Paul; Frebel, Anna; Ryan, Sean G. (2013)
      We examine the metallicity distribution function (MDF) and fraction of carbon-enhanced metal-poor (CEMP) stars in a sample that includes 86 stars with [Fe/H] <= -3.0, based on high-resolution, high signal-to-noise spectroscopy, ...
    • The Most Metal-Poor Stars. IV : The Two Populations with [Fe/H] <~ -3.0 

      Norris, John; Yong, David; Bessell, Michael; Christlieb, Norbert; Asplund, Martin; Gilmore, G.F.; Wyse, Rosemary F. G.; Beers, Timothy; Barklem, Paul; Frebel, Anna; Ryan, Sean G. (2013-01-01)
      We discuss the carbon-normal and carbon-rich populations of Galactic halo stars having [Fe/H] lsim -3.0, utilizing chemical abundances from high-resolution, high signal-to-noise model-atmosphere analyses. The C-rich ...