Evolution of Mid-IR Excess Around Sun-like Stars: Constraints on Models of Terrestrial Planet Formation

TL;DR

This study uses Spitzer observations to analyze the frequency and evolution of 24 micron excess emission around sun-like stars, providing insights into debris disks and terrestrial planet formation over stellar lifetimes.

Contribution

It presents the first unbiased survey of 24 micron excess in a large sample of sun-like stars across a wide age range, constraining models of planetary system development.

Findings

8.5-19% of young stars show excess emission indicating debris disks.

Less than 4% of older stars exhibit such excess, showing decline over time.

Results support the hypothesis that many sun-like stars form terrestrial planets.

Abstract

We report observations from the Spitzer Space Telescope (SST) regarding the frequency of 24 micron excess emission toward sun-like stars. Our unbiased sample is comprised of 309 stars with masses 0.7-2.2 Msun and ages from <3 Myr to >3 Gyr that lack excess emission at wavelengths <=8 microns. We identify 30 stars that exhibit clear evidence of excess emission from the observed 24/8 micron flux ratio. The implied 24 micron excesses of these candidate debris disk systems range from 13 % (the minimum detectable) to more than 100 % compared to the expected photospheric emission. The frequency of systems with evidence for dust debris emitting at 24 micron ranges from 8.5-19 % at ages <300 Myr to < 4 % for older stars. The results suggest that many, perhaps most, sun-like stars might form terrestrial planets.