Discovery of two TNO-like bodies in the asteroid belt

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.

Recent formation and likely cometary activity of near-Earth asteroid pair 2019 PR2 -- 2019 QR6

“…These spectral properties are indicative of an origin outside of the Main Belt (e.g., Hasegawa et al, 2021). As these object's colors are intermediate to that of Red Group Trojans and the reddest of Centaurs (Fig.…”

“…From a compositional perspective, iron-rich silicates and tholin-like organics may be responsible for reddening surfaces in the outer Solar System (e.g., Sharkey et al, 2019;Hasegawa et al, 2021). However, given the complexity of pair formation from a rubble-pile precursor (Walsh et al, 2008;Scheeres, 2007), it is unlikely that any separation event could have produced components with significantly different compositions.…”