The Correlation Between Metallicity and Debris Disk mass

TL;DR

This study demonstrates a correlation between initial dust masses in debris disks and the metallicities of their host stars, using a large, well-analyzed sample and accounting for various uncertainties and evolutionary factors.

Contribution

It introduces a comprehensive analysis linking debris disk dust masses with stellar metallicity, improving on past efforts by including upper limits, evolution, and uncertainties.

Findings

Disk-bearing stars rarely have metallicities below -0.2.

Warm debris disk masses are absent around stars with [Fe/H] < -0.085.

A significant correlation exists between initial dust mass and stellar metallicity.

Abstract

We find that the initial dust masses in planetary debris disks are correlated with the metallicities of their central stars. We compiled a large sample of systems, including Spitzer, the Herschel DUNES and DEBRIS surveys, and WISE debris disk candidates. We also merged 33 metallicity catalogs to provide homogeneous [Fe/H] and $\sigma_{[Fe/H]}$ values. We analyzed this merged sample, including 222 detected disks (74 warm and 148 cold) around a total of 187 systems (some with multiple components) and 440 disks with only upper limits (125 warm and 315 cold), around a total of 360 systems. The disk dust masses at a common early evolutionary point in time were determined using our numerical disk evolutionary code, evolving a unique model for each of the 662 disks backward to an age of 1 Myr. We find that disk-bearing stars seldom have metallicities less than [Fe/H] = -0.2 and that the distribution of warm component masses lacks examples with large mass around stars of low metallicity ([Fe/H] < -0.085). Previous efforts to find a correlation have been largely unsuccessful; the primary improvements supporting our result are: 1.) basing the study on dust masses, not just infrared excess detections; 2.) including upper limits on dust mass in a quantitative way; 3.) accounting for the evolution of debris disk excesses as systems age; 4.) accounting fully for the range of uncertainties in metallicity measurements; and 5.) having a statistically large enough sample.