Polarimetry of extra-solar planetary systems

Hans Martin Schmid

Light reflected from planets in circumstellar disks is polarized. Because this scattering polarization can be quite high, polarimetry provides a sensitive differential technique for detecting and characterizing circumstellar disks and extra-solar planets with upcoming instruments like the SPHERE ``VLT planet finder'' instrument. In this talk we give an overview of the capabilities of SPHERE polarimetry for the investigation of extra-solar planetary systems. In addition we discuss model calculation of the polarization signal from planets, compare the results with measurements from solar system objects and discuss the diagnostic potential of polarimetry for the determination of the atmospheric structure of extra-solar planets.