SDSS-based taxonomic classification and orbital distribution of main belt asteroids

¹ Observatório Nacional (COAA), rua Gal. José Cristino 77, São Cristóvão, CEP 20921-400 Rio de Janeiro RJ, Brazil e-mail: carvano@on.br
² Universidade Federal do Rio de Janeiro/Observatório do Valongo, Lad.Pedro Antônio, 43, 20080-090 Rio de Janeiro, Brazil

Received: 18 September 2009
Accepted: 4 November 2009

Abstract

Aims. The present paper aims to derive a new classification scheme for SDSS MOC asteroid colors that is compatible with previous taxonomies based on spectroscopic data. The distribution of these can give important clues to the formation and evolution of this region of the Solar System, as well as to locate candidates with mineralogically interesting spectra for detailed observations.

Methods. The methodology is based on the large database SDSS MOC4. Templates of the main taxonomic classes are derived and then used to classify the asteroid observations in the SDSS MOC4. The derived taxonomic scheme is compatible with the Bus taxonomy and is suitable to the peculiarities of the SDSS observations, in particular, the low spectral resolution.

Results. Density maps of the seven classes defined by the method reproduce classical results for the background which is mainly dominated by the class in the inner belt and by the and the classes beyond 2.8 AU. It also shows new structures, such as the fact that the and seem evenly distributed in the inner belt while in the outer belt the class increase in density only at the location of asteroid families. Although their overall distribution is similar, the class seems less frequently associated with large families than do the class asteroids. Although only clustering around the Vesta family, the class asteroidsnappear scattered all around the main belt. Besides the lack satisfactory explanations of most of the highlighted features, they may provide strong constraints on the models of the formation and evolution of the Solar System.