Bibcode
Smith, Linda J.; Esteban, Cesar
Bibliographical reference
Space Science Reviews, Volume 66, Issue 1-4, pp. 263-270
Advertised on:
3
1993
Journal
Citations
3
Refereed citations
3
Description
We 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. We 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. We find
lower temperatures for the four cooler late WN stars, particularly for
the two WN6 stars. For the nebulae surrounding these stars, we find that
the model flux distributions produce too much nebular ionization. We
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, we derive a
temperature of 105 000 K, somewhat less than previous estimates. The
positions of our 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, we find that our derived luminosities are too
low, giving an initial mass range of 25 40 M&sun;, below
that expected for the majority of WR stars.