The albedo-color diversity of transneptunian objects

TL;DR

This study reveals two distinct surface types among transneptunian objects based on albedo and color, indicating a compositional discontinuity in the early solar system.

Contribution

It provides the first clear evidence of a color-albedo bimodality in transneptunian objects linked to their formation locations.

Findings

Two main surface types identified: redder/higher albedo and darker/neutral color.

Objects in stable Kuiper belt orbits are confined to the bright-red group.

Supports the idea of a compositional boundary in the early solar system.

Abstract

We analyze albedo data obtained using the Herschel Space Observatory that reveal the existence of two distinct types of surface among midsized transneptunian objects. A color-albedo diagram shows two large clusters of objects, one redder and higher albedo and another darker and more neutrally colored. Crucially, all objects in our sample located in dynamically stable orbits within the classical Kuiper belt region and beyond are confined to the bright-red group, implying a compositional link. Those objects are believed to have formed further from the Sun than the dark-neutral bodies. This color-albedo separation is evidence for a compositional discontinuity in the young solar system.