A portrait of the extreme Solar System object 2012 DR30

TL;DR

2012 DR30 is a large, low-albedo Solar System object with a highly eccentric, unstable orbit, likely recently migrated from distant regions, and exhibits unique surface features among similar bodies.

Contribution

This study provides detailed size, albedo, and surface property measurements of 2012 DR30, revealing its unique orbit and surface features compared to other trans-Neptunian objects.

Findings

Size of 185 km in diameter

Albedo of approximately 8%

Unusual absorption feature in Z-band

Abstract

2012 DR30 is a recently discovered Solar System object on a unique orbit, with a high eccentricity of 0.9867, a perihelion distance of 14.54 AU and a semi-major axis of 1109 AU, in this respect outscoring the vast majority of trans-Neptunian objects. We performed Herschel/PACS and optical photometry to uncover the size and albedo of 2012 DR30, together with its thermal and surface properties. The body is 185 km in diameter and has a relatively low V-band geometric albedo of ~8%. Although the colours of the object indicate that 2012 DR30 is an RI taxonomy class TNO or Centaur, we detected an absorption feature in the Z-band that is uncommon among these bodies. A dynamical analysis of the target's orbit shows that 2012 DR30 moves on a relatively unstable orbit and was most likely only recently placed on its current orbit from the most distant and still highly unexplored regions of the Solar System. If categorised on dynamical grounds 2012 DR30 is the largest Damocloid and/or high inclination Centaur observed so far.