The stellar properties of Sk 41 ( AB4 , WN5h ) , the only known single Wolf-Rayet star in the SMC , are derived from ultraviolet ( IUE ) , optical ( AAT ) and near-IR ( NTT ) spectroscopy .
Contrary to expectations , the stellar properties of Sk 41 are typical of equivalent WN stars in the Galaxy and LMC , with T _ { \ast } \sim 42kK , log ( L / L _ { \odot } ) =5.7 , v _ { \infty } =1300 km s ^ { -1 } , \dot { M } / \sqrt { f } =3 \times 10 ^ { -5 } M _ { \odot } yr ^ { -1 } , and H/He \sim 2 by number , where f is the volume filling factor .
The stellar luminosity of Sk 41 is 50 % below the minimum value predicted by single star evolutionary models at the metallicity of the SMC .

Emission line luminosities of He ii \lambda 4686 and C iv \lambda \lambda 5801-12 in SMC WR stars are not systematically lower than their Galactic and LMC counterparts .
From 43 late-type and 59 early-type WN stars , log L _ { \lambda } ^ { HeII } = 36.0 erg s ^ { -1 } and 35.8 erg s ^ { -1 } , respectively , while log L _ { \lambda } ^ { CIV } =36.5 erg s ^ { -1 } .
from 25 early-type WC stars .
This new calibration has application in deriving WR populations in young starburst galaxies .

Synthetic WN models are calculated with identical parameters except that metal abundances are varied .
Following the Smith et al .
WN classification scheme , CNO equilibrium models reveal that earlier spectral types are predicted at lower metallicity , i.e .
WN3–4 at 0.04 Z _ { \odot } versus WN6 at 1.0 Z _ { \odot } .
This provides an explanation for the trend towards earlier WN spectral types at low metallicity .