Space weathering of asteroids: similarities and discrepancies between Main Belt asteroids and NEOs

A sample of 35 C-complex objects is present among near-Earth objects. In spite of the poor statistics, some striking differences compared to Main Belt asteroids can be established: for instance the percentage of near-Earth objects (NEOs) showing hydration features is very small. Moreover the spectral slope of C-complex NEOs seems to be anti-correlated with the exposure to the ion flux coming from the Sun, in contrast with the general behavior of C-complex Main Belt asteroids (and of most asteroids, in general). We discuss some possible implications and suggest some preliminary partial explanations.