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Table 13

Stellar and wind parameters determined from consistently calculated atmospheric models along with UV diagnostics of the WN5h star R136a3 (cf. Fig. 22).

Parameter           Model A+ Model A

Teff (K) 52 000 52 000
R (R) 24.2 24.2
log L (L) 6.59 6.59
M (M) 95 110
XH (%) 40 40
XC (%) 0.028 0.014
XN (%) 0.43 0.43
XO (%) 0.004 0.004
XFea (%) ssa 0.19
XNia (%) ssa 0.011
v (km s-1) 2250 2900
(10-6   M/yr) 33.0 32.3

Notes. With respect to the stellar and wind parameters determined by Crowther et al. (2010) (cf. Table 12), the main difference to the parameters of our prototype model – model “A+” – is the mass of the object M. From our analysis it turned out that the mass must be lowered by almost 30% in order to reproduce the dynamical parameters and the UV spectrum of the star. By means of the parameters determined by model “A” we show further, that the problem of a too high terminal velocity v (cf. Table 12) can not been solved just by a moderate reduction of M and an additional enhancement of the abundances of the elements which increase (cf. Pauldrach 1987) – namely iron and nickel –, because although increases in this case to the required value, v remains at a value which is still too high.

(a)

For model “A” the iron and nickel abundance has been increased by a factor of three relative to the adopted scaled solar abundance values.

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