Short Lifetime of Protoplanetary Disks in Low-metallicity Environments

TL;DR

This study shows that protoplanetary disks in low-metallicity environments dissipate much faster than in solar-metallicity regions, potentially explaining the observed planet-metallicity correlation.

Contribution

First observational evidence indicating that disk lifetime decreases with metallicity, providing insights into planet formation timescales in different environments.

Findings

Disk fractions decline rapidly in <1 Myr in low-metallicity clusters

Disk lifetime shortens with decreasing metallicity, possibly with a 10^Z dependence

Results suggest shorter disk lifetimes may explain the planet-metallicity correlation

Abstract

We studied near-infrared disk fractions of six young clusters in the low-metallicity environments with [O/H$] \sim -0.7$ using deep $JHK$ images with Subaru 8.2\,m telescope. We found that disk fraction of the low-metallicity clusters declines rapidly in $<$1\,Myr, which is much faster than the $\sim$5--7\,Myr observed for the solar-metallicity clusters, suggesting that disk lifetime shortens with decreasing metallicity possibly with an $\sim$$10^Z$ dependence. Since the shorter disk lifetime reduces the time available for planet formation, this could be one of the major reasons for the strong planet--metallicity correlation. Although more quantitative observational and theoretical assessments are necessary, our results present the first direct observational evidence that can contribute to explaining the planet--metallicity correlation.