Asteroid-Comet Continuum Objects in the Solar System

TL;DR

This review discusses small solar system bodies exhibiting both asteroid and comet characteristics, emphasizing their continuum nature and significance for understanding solar system diversity.

Contribution

It introduces the concept of continuum objects, highlighting their properties and importance in studying regions of the solar system not accessible via classical comets.

Findings

Continuum objects display a range of properties between asteroids and comets.

They provide insights into primitive compositions and material ejection processes.

These bodies help sample distant solar system regions.

Abstract

In this review presented at the Royal Society meeting, "Cometary Science After Rosetta", I present an overview of studies of small solar system objects that exhibit properties of both asteroids and comets (with a focus on so-called active asteroids). Sometimes referred to as "transition objects", these bodies are perhaps more appropriately described as "continuum objects", to reflect the notion that rather than necessarily representing actual transitional evolutionary states between asteroids and comets, they simply belong to the general population of small solar system bodies that happen to exhibit a continuous range of observational, physical, and dynamical properties. Continuum objects are intriguing because they possess many of the properties that make classical comets interesting to study (e.g., relatively primitive compositions, ejection of surface and subsurface material into space where it can be more easily studied, and orbital properties that allow us to sample material from distant parts of the solar system that would otherwise be inaccessible), while allowing us to study regions of the solar system that are not sampled by classical comets.