Analysis of the Herschel DEBRIS Sun-like star sample

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 AM. 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 underlying 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 > 5 × 10 −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.

Population synthesis of exocometary gas around A stars

“…We take the same approach as for A stars, and we simulate a population of FGK stars following the results by Sibthorpe et al (2018) that used both Spitzer and Herschel FIR photometry of 275 FGK stars to fit a collisional evolution model, similar to Wyatt et al (2007b). That study found best-fit parameters A = 5.5 × 10 5 , B = 0.1 and γ = −1.7.…”

Twisted debris: how differential secular perturbations shape debris disks

“…Despite its relatively low total mass, dust in circumstellar debris disks is readily detected because of its high specific cross section. Current far-infrared detection rates are as high as ∼ 20 % for nearby stars (Eiroa et al 2013;Montesinos et al 2016;Sibthorpe et al 2018), indicating how ubiquitous these disks are. Akin to the Edgeworth-Kuiper belt in the Solar system, debris disks are often found at distances of tens or more than one hundred au from their host stars (e.g.…”

The Statistics of Extended Debris Disks Measured with Gaia and Planck

“…This constraint is consistent with analyses using Herschel and Spitzer. Sibthorpe et al (2017); Eiroa et al (2013); Trilling et al (2008), for instance, have measured hundreds of debris disks around a sample of typically brighter stars using such surveys, and find f disk in the range of 10-30% .…”