Polarimetry of Solar System Gaseous Planets

With the ESO 3.6-m telescope and EFOSC2 we have observed Solar System planets to investigate limb polarisation in detail. Our observations were successful and we can report the detection of limb polarisation in Uranus and Neptune. In addition spatially resolved long-slit spectropolarimetry was obtained for the first time for all the gaseous planets. The observations reveal a decrease of limb polarisation with increasing wavelength and an enhanced polarisation in the methane bands against the adjacent continuum. We describe our measurements and also discuss the diagnostic potential of such data for the investigation of the atmospheric structure of giant planets and the properties of their scattering particles.