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Rb-Rich Asymptotic Giant Branch Stars in the Magellanic Clouds
(2009-11)
We present high-resolution (R similar to 60,000) optical spectra of a carefully selected sample of heavily obscured and presumably massive O-rich asymptotic giant branch (AGB) stars in the Magellanic Clouds. We report the ...
Lithium Abundances In Nearby FGK Dwarf And Subgiant Stars: Internal Destruction, Galactic Chemical Evolution, And Exoplanets
(2012-09)
We derive atmospheric parameters and lithium abundances for 671 stars and include our measurements in a literature compilation of 1381 dwarf and subgiant stars. First, a "lithium desert" in the effective temperature (T-eff) ...
The (Cn)-N-14/(Cn)-N-15 Ratio in Diffuse Molecular Clouds
(2015-05)
We report the first detection of (CN)-N-15 in diffuse molecular gas from a detailed examination of CN absorption lines in archival spectra, obtained with the Ultraviolet and Visual Echelle Spectrograph of the Very Large ...
The Chemical Composition Of Cernis 52 (BD+31 Degrees 640)
(2009-11)
We present an abundance analysis of the star Cernis 52 in whose spectrum we recently reported the naphthalene cation in absorption at 6707.4 angstrom. This star is on a line of sight to the Perseus molecular complex. The ...
Are C-60 Molecules Detectable In Circumstellar Shells Of R Coronae Borealis Stars?
(2011-03)
The hydrogen-poor, helium-rich, and carbon-rich character of the gas around R Coronae Borealis (RCB) stars has been suggested to be a site for formation of C-60 molecules. This suggestion is not supported by observations ...
Oxygen Isotopic Ratios In Cool R Coronae Borealis Stars
(2010-05)
We investigate the relationship between R Coronae Borealis (RCB) stars and hydrogen-deficient carbon (HdC) stars by measuring precise (16)O/(18)O ratios for five cool RCB stars. The (16)O/(18)O ratios are derived by spectrum ...
Rubidium And Lead Abundances In Giant Stars Of The Globular Clusters M4 And M5
(2008-02)
We present measurements of the neutron-capture elements Rb and Pb for bright giants in the globular clusters M4 and M5. The clusters are of similar metallicity ([Fe/ H] similar or equal to -1.2), but M4 is decidedly s-process ...
Origin of Lithium Enrichment in K Giants
(2011-03)
In this Letter, we report on a low-resolution spectroscopic survey for Li-rich K giants among 2000 low-mass (M <= 3 M-circle dot) giants spanning the luminosity range from below to above the luminosity of the clump. Fifteen ...
Fluorine In R Coronae Borealis Stars
(2008-02)
Neutral fluorine (F I) lines are identified in the optical spectra of several R Coronae Borealis stars (RCBs) at maximum light. These lines provide the first measurement of the fluorine abundance in these stars. Fluorine ...