The fundamental parameters of the central stars of eight WR ring nebulae.

Smith, L. J.; Esteban, C.
Referencia bibliográfica

Meeting: Evolution of massive stars, p. 263 - 270

Fecha de publicación:
1994
Número de autores
2
Número de autores del IAC
1
Número de citas
1
Número de citas referidas
0
Descripción
The authors describe work that has recently been completed on deriving the fundamental parameters of eight WR stars through the photoionization modelling of their surrounding nebulae using non-LTE WR flux distributions. The resulting effective temperatures range from 57,000-71,000 K for the WN4-5 stars and <30,000-42,000 K for the WN6-8 stars. The derived stellar parameters are compared with those obtained from stellar emission line modelling. The authors find good agreement for the hot early WN stars, indicating that the non-LTE WR flux distributions have essentially the correct shape in the crucial far-UV region. They find lower temperatures for the four cooler late WN stars, particularly for the two WN6 stars. For the nebulae surrounding these stars, the authors find that the model flux distributions produce too much nebular ionization. They suggest that these discrepancies arise because of the lack of line-blanketing in the WR atmospheres. For the WO1 central star of G2.4+1.4, with strong nebular He II 4686 A emission, the authors derive a temperature of 105,000 K, somewhat less than previous estimates. The positions of their eight WR stars on the H-R diagram are compared with the evolutionary tracks of Maeder (1990) for solar metallicity. In common with previous workers, the authors find that their derived luminosities are too low, giving an initial mass range of 25-40 Msun, below that expected for the majority of WR stars.