Analysis of the Herschel DEBRIS Sun-like star sample

TL;DR

This study analyzes debris disks around Sun-like stars using Herschel data, revealing detection rates, disk properties, and evolutionary insights, with some systems likely resulting from transient events or atypical formation histories.

Contribution

It provides the first comprehensive survey of debris disks around Sun-like stars with detailed modeling of their properties and evolution, highlighting the diversity and potential origins of these disks.

Findings

17.1% detection rate of debris disks among F-K stars

Most disks have fractional luminosity ~10^-5 and are located 7-40 AU from the star

Hot and bright debris systems likely result from transient or atypical events

Abstract

This paper presents a study of circumstellar debris around Sun-like stars using data from the Herschel DEBRIS Key Programme. DEBRIS is an unbiased survey comprising the nearest ~90 stars of each spectral type A-M. Analysis of the 275 F-K stars shows that excess emission from a debris disc was detected around 47 stars, giving a detection rate of 17.1+2.6-2.3 per cent, with lower rates for later spectral types. For each target a blackbody spectrum was fitted to the dust emission to determine its fractional luminosity and temperature. The derived under- lying distribution of fractional luminosity versus blackbody radius in the population showed that most detected discs are concentrated at f ~ 10^-5 and at temperatures corresponding to blackbody radii 7-40 AU, which scales to ~40 AU for realistic dust properties (similar to the current Kuiper belt). Two outlying populations are also evident; five stars have exceptionally bright emission ( f > 5x10^-5), and one has unusually hot dust < 4 AU. The excess emission distributions at all wavelengths were fitted with a steady-state evolution model, showing these are compatible with all stars being born with a narrow belt that then undergoes collisional grinding. However, the model cannot explain the hot dust systems - likely originating in transient events - and bright emission systems - arising potentially from atypically massive discs or recent stirring. The emission from the present-day Kuiper belt is predicted to be close to the median of the population, suggesting that half of stars have either depleted their Kuiper belts (similar to the Solar System), or had a lower planetesimal formation efficiency.