The inner region of the asteroid Main Belt: a spectroscopic and dynamic analysis

¹ Observatório Nacional, R. Gal. José Cristino 77, 20921-400, Rio de Janeiro, Brazil e-mail: [alvarez;lazzaro]@on.br; duffard@mps.mpg.de
² Instituto de Astronomia, Geofísica e Ciências Atmosféricas, USP, Rua do Matão 1226, 05508-900 São Paulo, Brazil e-mail: tatiana@astro.iag.usp.br

Received: 27 April 2006
Accepted: 17 August 2006

Abstract

Aims.To better understand the dynamical and collisional evolution of the inner Main Belt, we perform a visible spectroscopic survey and construct dynamical maps of the region.

Methods.The survey was performed between March 2002 and August 2005, at diverse observatories. The dynamical analysis was performed by the integration of 3131 massless particles homogeneously distributed in the region.

Results.We obtained new taxonomic classification for 88 asteroids representing a 13% increase in the sample of asteroids with know classification in the inner region of the Main Belt. The increase in the number of classified objects further confirms the notion that the inner region can be divided into three compositional zones: the innermost, where asteroids of the S-group concentrate, the outermost, where the C-group peaks, and in-between, with the highest concentration of V-type. The dynamical analysis shows that the region is covered by a dense web of mean-motion and secular resonances which may play an important role in the dynamical diffusion of the asteroids.