Quantitative comparisons between Wolf-Rayet stars in HD97950 and R136a

We present quantitative analyses of Wolf-Rayet stars in the cores of two giant H II regions, PID 97950 in NGC 3603 and R136a in 30 Dor, based on archive HST spectroscopy. We confirm WN6h+abs classifications for components Al, B, and C in HD 97950 (Drissen et al. 1995), while classifications for R136a(1-3) are revised from O3If/WN6 (de Koter et al. 1997) to WN5h. From detailed non-LTE analyses, we find that all the stars exhibit products of CNO-processed material at their surface, since they are rich in helium (H/He similar or equal to 3-6) and nitrogen (N/He similar or equal to 0.002-0.006). These stars are among the most luminous Wolf-Rayet stars known (log L/L. = 6.0-6.4), and are consequently very massive stars (M-init greater than or equal to 100 M.) at a relatively young age (similar to 2 Myr), reminiscent of the WNL stars in Carina (Crowther et al. 1995a). We find that the methodology applied by Vacca & Conti (1992) to WR galaxies can account for the observed WN populations in these regions.