HUBBLE-SPACE-TELESCOPE DETECTION OF OPTICAL COMPANIONS OF WR-86, WR-146, AND WR-147 - WIND COLLISION MODEL CONFIRMED

Hubble Space Telescope (HST) Wide Field Planetary Camera 2 images of t he rado-binary Wolf-Rayet stars WR 146 and WR 147, as well as the 0.2 '' visual binary WR 86, resolve each of them into two very close optic al components. The colors of these optical pairs are similar, indicati ng that they are likely to be physically bound WR + OB systems at the same distance. Comparison of the locations of the optical components o f WR 146 and WR 147 with high-resolution radio maps strikingly demonst rates that the nonthermal radio components arise between the optical b inary components, closer to the OB component than the WR. This is as e xpected if the nonthermal radio emission results from the collision of the stellar winds of the binary components seen in the HST images. Th e similar magnitudes and colors determined for the components of WR 86 from our HST images, combined with an analysis of the unresolved, com bined WC7 + OB optical spectrum, indicates an absolute magnitude for t he WC7 component of about M-V similar to -5.