Interstellar Objects and Exocomets

TL;DR

This paper reviews the current understanding of exocomets and interstellar objects, covering their formation, characteristics, ejection mechanisms, and recent discoveries, highlighting recent advances and future prospects in the field.

Contribution

It provides a comprehensive overview of exocometary belts, the properties of interstellar objects, and discusses recent observational and theoretical progress in understanding these populations.

Findings

Discovery of the first two interstellar objects with surprising differences.

Advances in observational techniques have improved detection of exocomets.

Theoretical models explain mechanisms for ejection into interstellar space.

Abstract

In this chapter we review our knowledge of our galaxy's cometary population outside our Oort Cloud - exocomets and Interstellar Objects (ISOs). We start with a brief overview of planetary system formation, viewed as a general process around stars. We then take a more detailed look at the creation and structure of exocometary belts, as revealed by the unprecedented combination of theoretical and observational advances in recent years. The existence and characteristics of individual exocomets orbiting other stars is summarized, before looking at the mechanisms by which they may be ejected into interstellar space. The discovery of the first two ISOs is then described, along with the surprising differences in their observed characteristics. We end by looking ahead to what advances may take place in the next decade.