Compositional surface variety among the Centaurs

The Centaurs are a particular family of objects with orbits whose semimajor axes fall between those of Jupiter and Neptune. They are likely the transi tion objects between the Kuiper belt population and short-period comets. To investigate the nature of these particular objects, we have performed opti cal spectroscopic observations of five Centaurs. The results show a great d iversity among the reflectances of the five Centaurs. The colors do not see m to be related to the perihelion distance of the objects. We looked for we ak cometary emission features, in particular the CN-band emission at 3880 A ngstrom, but no CN emission feature has been detected within 3 sigma in any of the investigated spectra.