Debris disks around Sun-like stars

TL;DR

This study uses Spitzer observations of nearly 200 FGK stars to identify debris disks via infrared excess, revealing their incidence rates and potential age-related trends across spectral types.

Contribution

It provides the largest combined sample of Sun-like stars with debris disk data, revealing incidence rates and spectral type trends with implications for disk evolution.

Findings

Debris disk incidence is 4.2% at 24 microns and 16.4% at 70 microns among Sun-like stars.

No significant difference in debris disk rates across A, F, G, K spectral types.

Debris disk occurrence declines slowly beyond 1 billion years of stellar age.

Abstract

We have observed nearly 200 FGK stars at 24 and 70 microns with the Spitzer Space Telescope. We identify excess infrared emission, including a number of cases where the observed flux is more than 10 times brighter than the predicted photospheric flux, and interpret these signatures as evidence of debris disks in those systems. We combine this sample of FGK stars with similar published results to produce a sample of more than 350 main sequence AFGKM stars. The incidence of debris disks is 4.2% (+2.0/-1.1) at 24 microns for a sample of 213 Sun-like (FG) stars and 16.4% (+2.8/-2.9) at 70 microns for 225 Sun-like (FG) stars. We find that the excess rates for A, F, G, and K stars are statistically indistinguishable, but with a suggestion of decreasing excess rate toward the later spectral types; this may be an age effect. The lack of strong trend among FGK stars of comparable ages is surprising, given the factor of 50 change in stellar luminosity across this spectral range. We also find that the incidence of debris disks declines very slowly beyond ages of 1 billion years.