Spectrographic Observations of Peculiar Stars. II.
Abstract
RX Puppis.-Besides the strong emission lines of H, He I, and He Ix, this star is characterized by very intense lines of [Fe vii]; other highly ionized elements observed in the spectrum are [Ne v}, [Fe vii, and [Ca vu]. The object is very similar to CI Cygni; but the evidence for a late-type component is not as definite. The behavior of the forbidden lines is discussed. Recent variations in the spectra of T Coronae Borealis, Z Andromedae, RW Hydrae, R~ Ophiuchi, and AX Persei.-These five objects combine bright lines of high excitation and late-type spectra. In all cases their line-emission spectra observed in the last few years behave in the same way as in novae in their nebular stages; but the ejection velocities are smaller than in single novae, even of the slow type. `y Cassiopeiae.-The observations obtained in 1940 and 1941 were used to determine the contours of the broad lines from the reversing layer. These lines became gradually stronger as the lines produced by the outer shell grew weaker. The optical thickness for continuous radiation of the shell near its maximum development was about r1 = 0.2. 14 Comae Berenices.-The spectrum of this star consists of (i) an A5 component of moderate lumi- nosity whose H lines show strong Stark effect and whose lines of Mg ii, Si ii, Fen, and Fe i show rapid axial rotation and (2) the spectrum of a shell, which is responsible for sharp Ha but which is otherwise weak in H; the shell also gives rise to sharp lines of Ti ii, Cr ii, Sc ii, Ca ii, etc., and resembles the spec- trum of ~ Aurigae, except that H is much weaker and that the excitation temperature is lower. Some spectroscopic peculiarities of the shell may be accounted for by the hypothesis that the pressure within the shell is lower (perhaps by a factor of 10 or 100) than in normal supergiant reversing layers
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 1941
- DOI:
- Bibcode:
- 1941ApJ....94..291S