Ultraviolet and Visual Spectra of Gamma Cassiopeiae
1970; IOP Publishing; Volume: 162; Linguagem: Inglês
10.1086/150689
ISSN1538-4357
Autores Tópico(s)Stellar, planetary, and galactic studies
Resumoview Abstract Citations (53) References (49) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Ultraviolet and Visual Spectra of Gamma Cassiopeiae Bohlin, Ralph C. Abstract A rocket ultraviolet spectrum of Cas (BO.5 IVpe) was obtained with a resolution of about 2 A between 1060 and 2130 A on 1968 November 15. The strength of the interstellar La absorption line corresponds to an average density of 0.15 atoms of neutral hydrogen over the 220 pc to y Cas, while the absence of any observable lines of molecular hydrogen yielded an upper limit of 2.4 X 10- molecules . Possible interstellar absorption lines of C ii, N 1, and Si ii have widths that indicate that the low- density gas in which the lines arise may have an exponential velocity distribution with a dispersion of = 15 km . The C iv line at 1550 A is the only spectral feature with a P Cygni profile. OAO and visual spectra covering the wavelength range 1100-5000 A are also analyzed. The measured amount of Balmer continuous emission can be used to explain the weakness of the He i and other visual photospheric lines if the temperature and optical depth of the circumstellar envelope are known. If 2' Cas has an envelope consisting of discrete clouds, each of which has an optical depth of unity at 3647- A and an electron temperature of 20000 K, then the Balmer continuous emission is accounted for quantitatively and the line profiles in the ultraviolet and visual can be explained qualitatively. Publication: The Astrophysical Journal Pub Date: November 1970 DOI: 10.1086/150689 Bibcode: 1970ApJ...162..571B full text sources ADS | data products SIMBAD (9)
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