At http://phys.org/print362900111.html … NASAs Dawn spacecraft has been taking pictures of another small planet, or large asteroid, Ceres – which again displays evidence of unusual activity, including energetic particle bursts.
the irregular shape of craters on Ceres are reminiscent of craters on Saturn's moon Rhea – which appear to have an electro magnetic connection. Dawn's gamma ray and neutron spectrometer detected three bursts of energetic electrons which for the moment is not understood. It is suggested the burst of energy may have been sparked by the solar wind.