Colors and taxonomy of Centaurs and Trans-Neptunian Objects

TL;DR

This study uses visible and near-infrared photometry to classify and analyze the surface colors of 38 Centaurs and TNOs, revealing heterogeneity and correlations with their dynamics in the outer Solar System.

Contribution

It provides new taxonomic classifications for 10 objects and expands the sample of classified Centaurs and TNOs, enhancing understanding of their surface properties.

Findings

First-time color data for 10 objects

28 objects classified taxonomically in this study

Hints of surface heterogeneity in 4 objects

Abstract

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. Our aim is to investigate color properties of a large sample of minor bodies of the outer Solar System, and set their taxonomic classification. 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. (2005a) system. 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. 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. 2009a) 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.