Bibcode
Smith, L. J.; Esteban, C.
Bibliographical reference
Meeting: Evolution of massive stars, p. 263 - 270
Advertised on:
1994
Citations
1
Refereed citations
0
Description
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.