Journal: The Astrophysical Journal

  • Publication
    On the Origin of Neutron-capture Elements in r-I and r-II Stars: A Differential-abundance Analysis
    We present a strictly line-by-line differential analysis of a moderately r-process-enhanced star (r-I: HD 107752) with respect to a strongly r-process-enhanced...
  • Publication
    On the Origin of the Color-Magnitude Relation in the Virgo Cluster
    We explore the origin of the color-magnitude relation (CMR) of early-type galaxies in the Virgo Cluster using spectra of very high signal-to-noise ratio for six...
  • Publication
    On the Origin of the Type II Spicules: Dynamic Three-dimensional MHD Simulations
    Recent high temporal and spatial resolution observations of the chromosphere have forced the definition of a new type of spicule, "type II's," that are...
  • Publication
    On the Pair-instability Supernova Origin of J1010+2358
    The first (Population III) stars formed only out of H and He and were likely more massive than present-day stars. Massive Population III stars in the range 140...
  • Publication
    On The Parent Population of Radio Galaxies and the FR I-FR II Dichotomy
    We test the hypothesis that radio galaxies are a random subset of otherwise normal elliptical galaxies. Starting with the observed optical luminosity functions...
  • Publication
    On the Possible Existence of Short-Period g-Mode Instabilities Powered by Nuclear-Burning Shells in Post-Asymptotic Giant Branch H-Deficient (PG1159-Type) Stars
    We present a pulsational stability analysis of hot post-asymptotic giant branch (AGB) H-deficient pre-white dwarf stars with active He-burning shells. The...
  • Publication
    On the Presence of Metallofullerenes in Fullerene-rich Circumstellar Envelopes
    The presence of neutral C 60 fullerenes in circumstellar environments has been firmly established by astronomical observations as well as laboratory experiments...
  • Publication
    On the Progenitor of the Type Ic Supernova 2002ap
    This Letter presents wide-field optical and near-IR (UBVRIHαK') images of the galaxy M74 that were taken between 0.6 and 8.3 yr before the discovery of the Type...
  • Publication
    On the Purity of the ZZ Ceti Instability Strip: Discovery of More Pulsating DA White Dwarfs on the Basis of Optical Spectroscopy
    We report the discovery of two new ZZ Ceti pulsators, LP 133-144 and HE 1258+0123, selected on the basis of model atmosphere fits to optical spectroscopic data...