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.