Protoplanetary Disk Survival Time-scales: A Blind Survey of Young Clusters up to 100 Myr in the Solar Vicinity

TL;DR

This study investigates protoplanetary disk lifetimes in nearby young clusters up to 100 Myr, revealing wavelength-dependent decay timescales, persistent disks in older systems, and slower dissipation around lower-mass stars.

Contribution

It provides a comprehensive analysis of disk dissipation timescales across multiple wavelengths and stellar ages, highlighting the longevity of some disks beyond typical dissipation periods.

Findings

Disk fraction decreases with age across all wavelengths.

Outer disk regions evolve more slowly than inner regions.

Some disks persist up to 100 Myr, longer than previously thought.

Abstract

We study the protoplanetary disk lifetimes using a large sample of young stellar objects in nearby clusters. To investigate the final phase of disk dissipation, we selected 32 clusters, located within 500 pc and aged between 1 and 100 Myr, with membership determined using Gaia data. The Age and mass information of the sources are obtained through spectral energy distribution (SED) analysis and using evolutionary models of various ages. Using the IR data from 2MASS and WISE catalogues, we employ three methods to identify disks across the different wavelength regimes (1.1- 22 $\mu$m). We find that disk fraction consistently decreases as stellar systems age, a trend observed across all wavelengths included in this study. However, there is an increase in the time scale of disk decay as wavelength increases, with characteristic timescales of $\tau_{\text{short}}$ = 1.6 $\pm$ 0.1 Myr for shorter wavelengths (1.6-4.6 $\mu$m) versus $\tau_{\text{W3}}$ = 4.4 $\pm$ 0.3 Myr for 12 $\mu$m. This supports the idea that outer disk regions evolve more slowly. Notably, we detect infrared excesses at 12 $\mu$m and 22 $\mu$m in relatively older systems ($>$10 Myr), with some disks with estimated ages up to $\sim$ 100 Myr. Among these, we identify a population of full disks that persist beyond the typical dissipation timescale. We also observe that the median mass of disk-hosting stars decreases from 0.62 $M_\odot$ to 0.27 $M_\odot$ in clusters younger and older than 40 Myr, respectively, indicating slower disk dissipation around lower-mass stars. We identify 33 transitional disk candidates using various color-color diagrams. Using LAMOST DR8 optical spectra and H-alpha equivalent widths, we identify possible accretors and estimate their mass accretion rates, finding most are younger than 10 Myr.