Optical linear polarization measurements of WR massive binary and single
  stars
  We present optical (UBVRI) linear polarimetric observations of 8 Wolf-Rayet
(WR) massive binaries and single stars. We have corrected the observed values
for the interstellar extinction and polarization by the interstellar medium to
obtain the intrinsic polarization and position angle. We find three highly
polarization stars between 5% and 10% (WR1, WR5 and WR146), three between 3%
and 4% (WR2, WR3 and WR4), and two between 1% and 2% (WR137 and WR140).
Moreover, 5 stars show increasing degree of polarization to shorter wavelengths
(e.g WR 146) indicative with asymmetric circumstellar envelope and 3 have
nearly constant polarization within the errors (e.g WR 140).
