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Hubble Space Telescope Near-Ultraviolet Spectroscopy Of The Bright CEMP-No Star BD+44 Degrees 493
(2014-07)
We present an elemental-abundance analysis, in the near-ultraviolet (NUV) spectral range, for the extremely metal-poor star BD+44 degrees 493 a ninth magnitude subgiant with [Fe/H] = -3.8 and enhanced carbon, based on data ...
Detection of the Second r-Process Peak Element Tellurium in Metal-Poor Stars
(2012-03)
Using near-ultraviolet spectra obtained with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope, we detect neutral tellurium in three metal-poor stars enriched by products of r-process nucleosynthesis, ...
Chemical Signatures Of The First Galaxies: Criteria For One-Shot Enrichment
(2012-11)
We utilize metal-poor stars in the local, ultra-faint dwarf galaxies (UFDs; L-tot <= 10(5) L-circle dot) to empirically constrain the formation process of the first galaxies. Since UFDs have much simpler star formation ...
The Chemical Imprint Of Silicate Dust On The Most Metal-Poor Stars
(2014-02)
We investigate the impact of dust-induced gas fragmentation on the formation of the first low-mass, metal-poor stars (<1 M-circle dot) in the early universe. Previous work has shown the existence of a critical dust-to-gas ...
New Detections Of Arsenic, Selenium, And Other Heavy Elements In Two Metal-Poor Stars
(2014-08)
We use the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope to obtain new high-quality spectra covering the 1900 <= lambda <= 2360 angstrom wavelength range for two metal-poor stars, HD 108317 and ...
HE 1327-2326, An Unevolved Star With Fe/H <-5.0. III. Does Its Atmosphere Reflect Its Natal Composition?
(2009-06)
Based on spectroscopic constraints derived from nonlocal thermodynamic equilibrium line formation, we explore the likely range of stellar parameters (T-eff and log g) for the hyper-metal-poor (HMP) star HE 1327-2326. ...
The Chemical Abundances Of Stars In The Halo (CASH) Project. II. A Sample Of 14 Extremely Metal-Poor Stars
(2011-11)
We present a comprehensive abundance analysis of 20 elements for 16 new low-metallicity stars from the Chemical Abundances of Stars in the Halo (CASH) project. The abundances have been derived from both Hobby-Eberly Telescope ...
New Hubble Space Telescope Observations of Heavy Elements in Four Metal-Poor Stars
(2012-12)
Elements heavier than the iron group are found in nearly all halo stars. A substantial number of these elements, key to understanding neutron-capture nucleosynthesis mechanisms, can only be detected in the near-ultraviolet. ...