Results 11 to 20 of about 23,100 (197)
Hypervelocity Stars. II. The Bound Population [PDF]
The Astrophysical Journal, 2007 Hypervelocity stars (HVSs) are stars ejected completely out of the Milky Way by three-body interactions with the massive black hole in the Galactic center. We describe 643 new spectroscopic observations from our targeted survey for HVSs. We find a significant (3.5 sigma) excess of B-type stars with large velocities +27510 kpc that are most plausibly ...
Brown, Warren R. +4 more
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Lithium 6104 Å in Population II stars [PDF]
Astronomy & Astrophysics, 2002 We have obtained echelle spectroscopy of 14 Population II objects selected from those previously observed by Bonifacio & Molaro (1997). For one object, HD 140283, we obtained exquisite data with the High Dispersion Spectrograph on the Subaru Telescope, with S/N exceeding 1000 per 0.018A pixel.
Ford, A. +7 more
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The Transition from Population III to Population II Stars [PDF]
The Astrophysical Journal, 2004 4 pages, 2 figures.
Fang, Taotao, Cen, Renyue
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Cosmic reionization by stellar sources: Population II stars [PDF]
Monthly Notices of the Royal Astronomical Society, 2003 We study the reionisation of the Universe by stellar sources using a numerical approach that combines fast 3D radiative transfer calculations with high resolution hydrodynamical simulations. Ionising fluxes for the sources are derived from intrinsic star formation rates computed in the underlying hydrodynamical simulations.
Sokasian, Aaron +3 more
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Lithium In Population II Stars [PDF]
Highlights of Astronomy, 1995 AbstractSince the work of Spite & Spite (1982), halo main sequence turn-off stars have usually been considered a site where Li synthesized in the Big-Bang is wholly preserved and uncontaminated by other Li sources. However, the interpretation of halo dwarf Li abundances has become more complex as new samples of halo star Li I observations have ...
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Surface convection in Population II stars [PDF]
Proceedings of the International Astronomical Union, 2008 AbstractThe initial surface abundances of Population II stars have been altered by the interplay between convection, rotational mixing and diffusion. In particular the shallower the outer convection zone the stronger the diffusion impact. We present preliminary results on constraining the extension of the convection zones of Population II stars thanks ...
Laurent Piau, Robert F. Stein
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The stochastic enrichment of Population II stars [PDF]
Monthly Notices of the Royal Astronomical Society, 2020 ABSTRACT We investigate the intrinsic scatter in the chemical abundances of a sample of metal-poor ([Fe/H] < −2.5) Milky Way halo stars. We draw our sample from four historic surveys and focus our attention on the stellar Mg, Ca, Ni, and Fe abundances.
Louise Welsh +2 more
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Binary Statistics Among Population II Stars [PDF]
International Astronomical Union Colloquium, 2004 AbstractPopulation II stars are old, metal-poor, Galactic halo stars with high proper motion. We have carried out a visual binary survey of 164 halo stars in the solar neighborhood (median distance 100 pc), using infrared speckle interferometry, adaptive optics, and wide field direct imaging.
H. Zinnecker, R. Köhler, H. Jahreiß
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Nucleosynthesis in Massive Population II Stars [PDF]
Symposium - International Astronomical Union, 1978 According to the conventional wisdom, the first stars formed in our Galaxy, including the massive ones responsible for most heavy element synthesis, must have had metal abundances much lower than solar. They may also have had somewhat lower helium abundances, corresponding to an enrichment ΔY/ΔZ = 2.7 ± 1.0 over the history of the Galaxy, a larger ...
David S. P. Dearborn, Virginia Trimble
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Flare Production of 6Li in Population II Stars [PDF]
The Astrophysical Journal, 1995 14 pages, 6 figs available on request, Tex, CITA/94 ...
Deliyannis, C. P., Malaney, R. A.
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