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Heavy-Element Dispersion In The Metal-Poor Globular Cluster M92
(2011-07)
Dispersion among the light elements is common in globular clusters (GCs), while dispersion among heavier elements is less common. We present detection of r-process dispersion relative to Fe in 19 red giants of the metal-poor ...
Transition Probabilities Of Astrophysical Interest In The Niobium Ions Nb+ And Nb2+
(2010)
Aims. We attempt to derive accurate transition probabilities for astrophysically interesting spectral lines of Nb II and Nb III and determine the niobium abundance in the Sun and metal-poor stars rich in neutron-capture ...
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 ...
Improved Ni I Log(gf) Values and Abundance Determinations in the Photospheres of the Sun and Metal-Poor Star HD 84937
(2014-04)
Atomic transition probability measurements for 371 Ni I lines in the UV through near-IR are reported. Branching fractions from data recorded using a Fourier transform spectrometer and a new echelle spectrograph are combined ...
The Abundances Of Neutron-Capture Species In The Very Metal-Poor Globular Cluster M15: A Uniform Analysis Of Red Giant Branch And Red Horizontal Branch Stars
(2011-06)
The globular cluster M15 is unique in its display of star-to-star variations in the neutron-capture elements. Comprehensive abundance surveys have been previously conducted for handfuls of M15 red giant branch (RGB) and ...
Characterizing The Heavy Elements In Globular Cluster M22 And An Empirical S-Process Abundance Distribution Derived From The Two Stellar Groups
(2011-11)
We present an empirical s-process abundance distribution derived with explicit knowledge of the r-process component in the low-metallicity globular cluster M22. We have obtained high-resolution, high signal-to-noise spectra ...
Improved V I Log(gf) Values and Abundance Determinations in the Photospheres of the Sun and Metal-Poor Star HD 84937
(2014-12)
New emission branching fraction measurements for 836 lines of the first spectrum of vanadium (V I) are determined from hollow cathode lamp spectra recorded with the National Solar Observatory 1 m Fourier transform spectrometer ...
Improved Log(gf) Values for Lines of Ti I and Abundance Determinations in the Photospheres of the Sun and Metal-Poor Star HD 84937 (Accurate Transition Probabilities for Ti I)
(2013-04)
New atomic transition probability measurements for 948 lines of Ti I are reported. Branching fractions from Fourier transform spectra and from spectra recorded using a 3 m echelle spectrometer are combined with published ...
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 ...
Europium, Samarium, And Neodymium Isotopic Fractions In Metal-Poor Stars
(2008-03)
We have derived isotopic fractions of europium, samarium, and neodymium in two metal-poor giants with differing neutron-capture nucleosynthetic histories. These isotopic fractions were measured from new high-resolution (R ...