Debris discs and comet populations around Sun-like stars: the Solar System in context

TL;DR

This study analyzes debris disks around Sun-like stars, revealing a smooth distribution of dust levels and suggesting the Solar System's Kuiper Belt is typical among low-dust systems, with implications for planetary habitability.

Contribution

It provides an empirical fit for debris disk dust levels across Sun-like stars and infers the rarity of systems like ours with gas giants and modest comet belts.

Findings

Most Sun-like stars have low dust debris levels.

The Solar System's Kuiper Belt is among the least dusty systems.

Systems like ours with gas giants and comet belts are rare, about a few percent.

Abstract

Numerous nearby FGK dwarfs possess discs of debris generated by collisions among comets. Here we fit the levels of dusty excess observed by Spitzer at 70$\umu$m and show that they form a rather smooth distribution. Taking into account the transition of the dust removal process from collisional to Poynting-Robertson drag, all the stars may be empirically fitted by a single population with many low-excess members. Within this ensemble, the Kuiper Belt is inferred to be such a low-dust example, among the last 10% of stars, with a small cometary population. Analogue systems hosting gas giant planets and a modest comet belt should occur for only a few per cent of Sun-like stars, and so terrestrial planets with a comparable cometary impact rate to the Earth may be uncommon. The nearest such analogue system presently known is HD154345 at 18pc, but accounting for survey completeness, a closer example should lie at around 10pc.