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Ubiquitous C IV 1550 Variability in B and Be Stars

Published online by Cambridge University Press:  23 September 2016

G. Sonneborn
Affiliation:
Astronomy Programs, Computer Sciences Corporation, Beltsville, Maryland, U.S.A.
M.P. Garhart
Affiliation:
Astronomy Programs, Computer Sciences Corporation, Beltsville, Maryland, U.S.A.
C.A. Grady
Affiliation:
Astronomy Programs, Computer Sciences Corporation, Beltsville, Maryland, U.S.A.

Extract

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Studies of line profile variability of the ultraviolet 1550 Angstrom resonance transitions of C IV in Be stars (Sonneborn et al. 1986; Grady, et al. 1986a,b) have prompted an investigation into the short- and long-term behavior of the C IV lines in other types of B stars. We present examples of two well-studied Be stars, Omega Orionis and 66 Ophiuchi, and two non-Be stars, Beta Cephei and the standard star Zeta Cassiopeiae. Zeta Cas is also known to be a 53 Per variable (see Cox 1983). The IUE SWP high-dispersion spectra of Beta Cep and Zeta Cas have been obtained from the IUE archives. It has been known for some years that the C IV line profiles in Beta Cep vary in a time scale of several days (Fishel and Sparks, 1980). However, it came as a surprise to discover C IV variability in Zeta Cas. Available data allow us to set an upper limit of several months for the time scale of Zeta Cas C IV variability. The principal difference between the C IV variability in Be and non-Be stars appears to be the magnitude and velocity range of the effect.

Type
III. The Circumstellar Gas
Copyright
Copyright © Cambridge University Press 1987

References

Cox, A.N. 1983, in “Astrophysical processes in upper-main-sequence stars”, Geneva Observatory.Google Scholar
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Sonneborn, G., Grady, C.A., Wu, C.-C., Hayes, D., Guinan, E.F., Henrichs, H.F. 1986, Astrophys. J., submitted.Google Scholar