Discovery of two TNO-like bodies in the asteroid belt

TL;DR

This study reports the discovery of two extremely red main-belt asteroids with spectral features indicating complex organics, suggesting they originated from the outer Solar System and were transported inward.

Contribution

It identifies two unique TNO-like bodies in the asteroid belt with spectral evidence of outer Solar System origin, expanding understanding of asteroid belt composition.

Findings

Both asteroids have the reddest spectral slopes among main-belt objects.

Spectroscopic analysis indicates presence of complex organic materials.

These bodies likely originated near Neptune and migrated inward.

Abstract

Two extremely red main-belt asteroids: 203 Pompeja and 269 Justitia, were identified from combined visible and near-infrared spectroscopic observations collected at the IRTF and SAO observatories. These two asteroids have a redder spectral slope than any other D-type body, which are the reddest objects in the asteroid belt, and similar to RR and IR-class objects found in the outer Solar System among trans-Neptunian objects and Centaurs. Spectroscopic results suggest the presence of complex organic materials on the surface layer of these asteroids, implying that they could have formed in the vicinity of Neptune and been transplanted to the main belt region during a phase of planetary migration. 203 Pompeia is the only very red asteroid known so far among the ~250 bodies with diameter larger than 110 km (i.e. presumably structurally intact) found in the asteroid belt. These discoveries add another piece of evidence that the main asteroid belt hosts a population of bodies that were formed in the outskirt of the Solar System.