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Abstract

Sanduleak (1971) has listed five stars, not apparently associated with planetary nebulae, which show very strong O VI 3811,34 Å emission. He pointed out that two of them are in the Magellanic Clouds and have absolute magnitudes comparable to those of classical (Population I) Wolf-Rayet stars. O VI emission is know to occur in some classical Wolf-Rayet stars, but not with the extreme strength shown by the Sanduleak stars. We have obtained absolute optical spectrophotometry (3100 – 7400Å) of all five of these stars, using the UCL Image Photon Counting System and RGO Spectrograph on the Anglo- Australian Telescope. Figure 1 shows their relative flux distributions. Inspection shows that Sand 1 is very lightly reddened, Sand 2 and 3 have intermediate reddening, and Sand 4 and 5 are heavily reddened. IUE ultraviolet spectrophotometry has been obtained of the first three stars; Sand 4 and 5 are too heavily reddened for IUE spectra to be feasible.

Keywords

Planetary Nebula Magellanic Cloud Helium Burning Shell Burning Core Helium Burning 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Barlow, M.U., Blades, U.C. and Hummer, D.G. 1980, Astrophys. J., 241, L27.ADSCrossRefGoogle Scholar
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Copyright information

© IAU 1982

Authors and Affiliations

  • M. J. Barlow
    • 1
  • D. G. Hummer
    • 2
  1. 1.Dept. of Physics and AstronomyUniversity College LondonLondonUK
  2. 2.Joint Institute for Laboratory AstrophysicsUniversity of Colorado and National Bureau of StandardsBoulderUSA

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