Colors and taxonomy of Centaurs and trans-Neptunian objects^*

¹ LESIA, Observatoire de Paris, 5 Place Jules Janssen, 92195 Meudon Principal Cedex, France e-mail: davide.perna@obspm.fr
² Università di Roma Tor Vergata, Italy
³ INAF-Osservatorio Astronomico di Roma, Italy
⁴ Université Paris Diderot – Paris 7, France
⁵ European Southern Observatory, Chile
⁶ Department of Astronomy, University of Maryland, USA

Received: 12 November 2009
Accepted: 30 November 2009

Abstract

Context. The study of the surface properties of Centaurs and trans-Neptunian objects (TNOs) provides essential information about the early conditions and evolution of the outer Solar System. Due to the faintness of most of these distant and icy bodies, photometry currently constitutes the best technique to survey a statistically significant number of them.

Aims. Our aim is to investigate color properties of a large sample of minor bodies of the outer Solar System, and set their taxonomic classification.

Methods. We carried out visible and near-infrared photometry of Centaurs and TNOs, making use, respectively, of the FORS2 and ISAAC instruments at the Very Large Telescope (European Southern Observatory). Using G-mode analysis, we derived taxonomic classifications according to the Barucci et al. ([CITE]a, AJ, 130, 1291) system.

Results. We report photometric observations of 31 objects, 10 of them have their colors reported for the first time ever. 28 Centaurs and TNOs have been assigned to a taxon.

Conclusions. We combined the entire sample of 38 objects taxonomically classified in the framework of our programme (28 objects from this work; 10 objects from DeMeo et al. [CITE], A&A, 493, 283) with previously classified TNOs and Centaurs, looking for correlations between taxonomy and dynamics. We compared our photometric results to literature data, finding hints of heterogeneity for the surfaces of 4 objects.