Search for rotational variation in the spectra of 253 Mathilde ?

253 Mathilde will be the next asteroid to be visited by a spacecraft (NEAR). Mathilde is an exceptional slow and complex rotatorwith a period of 17.4 days (Mottola et al., 1995). Binzel et al. (1996) have obtained the first spectrum ofMathilde in the visible range. To search for any variation on the asteroid surface, we have performed several observations in the visible range at the European Southern Observatory (ESO). The results show, combined with the spectrum of Binzel, that Mathilde’s surface is homogeneous over almost half of its rotational period. C type asteroids to which 253 Mathilde belongs, often show some absorption features due to acqueous alteration. Our spectroscopic surface analysis reveal featureless spectra.