INTERSTELLAR ULTRAVIOLET EXTINCTION TOWARDS THE NITROGEN SEQUENCE WOLF-RAYET STARS

With the archive IUE spectra of WR stars collected by Niedzielski and Rochowicz (1994) we obtain the UV extinction curve for WN stars. Using the two-color diagram method we can reach the goal almost independent ly, assuming only similar (b - upsilon)(o) for all single galactic WN stars, what is discussed on the basis of latest results. The resulting extinction curve differs strongly shortwards of the 2200 bump from th at of Seaton (1979) and is virtually identical to that of Krelowski an d Papaj (1992). Assuming the power law shape of WN continua we obtain a new value of (b - upsilon)(o) = -0.22 for single WN stars and presen t E(b-upsilon) for 34 galactic WN stars.