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Spectrophotometry of Ring Nebulæ Around Wolf-Rayet Stars∗

Published online by Cambridge University Press:  03 August 2017

Manfred W. Pakull
Manfred W. Pakull*
Affiliation:
Observatoire de Besançon, 25044 Besançon Cedex, France

Abstract

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Long-slit spectrophotometric observations of HII regions around Wolf-Rayet stars in the Galaxy, the Magellanic Clouds and in IC1613 are employed to measure the ionizing radiation from these stars. The sample includes all known WR stars in the SMC and 14 regions in the LMC comprising most of the known ring nebulæ. Apart from previously known HeII λ4686 emitting nebulæ around a few WO stars, HeIII regions were discovered within the nebulæ N76 and N79W which are being photoionized by the strong He+ Lyman continuum emission from the MagellanicWNE stars AB7 and Br2, respectively. The Zanstra blackbody temperatures and luminosities (80 000, 95 000 K and log L/LO = 5.4, 6.0, respectively) agree remarkably well with more elaborate WN model calculations and suggest a much higher bolometric correction (BC = −5.8 mag) than generally admitted for WN stars. The nebular λ4686 fluxes are several times higher than the corresponding broad stellar features suggesting that the highly ionized gas would remain detectable at much larger distances (i.e. in HII galaxies) than the underlying hot WNE population.

Type
Session VI. Enrichment
Information
Symposium - International Astronomical Union , Volume 143: Wolf–Rayet Stars and Interrelations with other Massive Stars in Galaxies , 1991 , pp. 391 - 396
Copyright
Copyright © Kluwer 1991 

References

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