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An Unstable Ofpe Star in the LMC

Published online by Cambridge University Press:  04 August 2017

Nolan R. Walborn*
Affiliation:
Laboratory for Astronomy and Solar Physics NASA/Goddard Space Flight Center

Extract

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The extreme Ofpe star HDE 269858 = Radcliffe 127 in the Large Magellanic Cloud (Walborn 1977), which has ejected nitrogen-rich material (Walborn 1982), was observed to be in a state of outburst on December 20, 1982. Spectroscopic observations at 2.5Å resolution with the Cerro Tololo Inter-American Observatory 1.5 meter SIT vidicon system showed a blue magnitude of 10.2, more than 1 magnitude brighter than previously, and a qualitatively changed spectrum. The Of emission features and the strong He I P Cygni profiles (especially λλ3889 and 4471) had disappeared, while the hydrogen Balmer emission remained very intense. IUE observations by S. Shore and N. Sanduleak provide evidence that the star has been in this “high” state since at least March 1981. Hence, a phenomenon related to those of P Cygni and/or Eta Carinae may be indicated. A current preprint by 0. Stahl, B. Wolf, G. Klare, A. Cassatella, J. Krautter, P. Persi, and M. Ferrari-Toniolo announces the prior discovery of the outburst at the European Southern Observatory in January 1982 and discusses extensive observations of its development, making a convincing case for interpretation of HDE 269858 as the hottest known Hubble-Sandage variable and a prime candidate for an 0 star becoming a WR via episodic enhanced mass loss.

Type
Stellar Populations
Copyright
Copyright © Reidel 1984 

References

Walborn, N. R. 1977, Ap. J. 215, 53.Google Scholar
Walborn, N. R. 1982, Ap. J. 256, 452.CrossRefGoogle Scholar