Polarization statistics of extra-solar systems

We have analysed the optical polarimetric properties of nearby intermediate-late type MS stars and examined in some detail the pecularities displayed by those known to have planets. We find that i) the polarization degree is not strictly correlated with the presence of planets; ii) there is a lack of high eccentricity planets at high optical linear polarization levels; iii) no clear correlation is seen between metallicity and polarization amongst extra-solar systems; iv) the contribution to the polarization by the interstellar medium seems to become effective only after ~70 pc