Astrophysical: Stellar composition

  • Publication
    A non-LTE stellar atmosphere study of nitrogen-rich early-type stars
    Spectrograms of a sample of nitrogen-rich early type stars (OBN stars) are analyzed differentially to normal stars of similar spectral types by means of NLTE...
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    A spectroscopic test for substellar objects
    We describe a spectroscopic test capable of providing direct confirmation of the substellar nature of brown dwarf candidates. While the conditions for...
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    Abundance gradient for 13 planetary nebulae in the Galaxy
    Via optical low-resolution long slit spectroscopy conducted at the 2.5 m INT in La Palma, He, O, N, Ne, A, and S abundances in 13 extended PN were calculated...
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    Abundances of light metals and NI in a sample of disc stars
    High resolution, high S/N spectra obtained using RETICON and CCD detectors are used to determine the abundances of Al, Si, Ca, Ni and Fe in 23 disc stars in the...
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    An improved evolutionary model for stellar population applied to NGC 2903
    The revised physical assumptions incorporated into a previously published evolutionary model for stellar population synthesis in galaxies (Casuso et al., 1989)...
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    An upper limit to the abundance of Be-9 in the Population II star HD 76932 from a high resolution spectrum with IUE
    A high resolution spectrum (Δλ = 0.2 Å) of the Population II star HD 76932 from the archive of the IUE satellite has been analysed in a search for measurable...
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    Asymptotic giant branch stars in NGC 6822: Probes of star formation history
    About 500 asymptotic giant branch (AGB) stars have been resolved and photometrically measured in the Local Group (LG) dwarf irregular galaxy NGC 6822. They draw...
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    Chemical composition of secondary stars in LMXBs: implications on the progenitors of black holes and neutron stars
    Recent studies of chemical abundances of secondary stars in low mass X-ray binaries have opened a new window to obtain information on the progenitors of black...
  • Publication
    IR spectrophotometry of bright carbon stars
    The results of medium resolution (R=600) spectrophotometry of 15 bright carbon stars of class N, obtained in the range of lambda:1 to 4.2 microns, are presented...