Most planets might have more than 5 Myr of time to form

TL;DR

This paper argues that the typical disk lifetime for low-mass stars is 5-10 million years, much longer than previously thought, which allows sufficient time for planet formation, contrasting with the shorter lifetimes observed in high-mass stars.

Contribution

It highlights the importance of considering observational biases and shows that low-mass stars have longer disk lifetimes, challenging previous estimates based on distant cluster studies.

Findings

Median disk lifetime for low-mass stars is 5-10 Myr.

Distant cluster studies overestimate disk lifetimes due to observational biases.

High-mass stars disperse disks faster, affecting lifetime estimates.

Abstract

The lifetime of protoplanetary disks is a crucial parameter for planet formation research. Observations of disk fractions in star clusters imply median disk lifetimes of 1 -- 3 Myr. This very short disk lifetime calls for planet formation to occur extremely rapidly. We show that young, distant clusters ($\leq$ 5 Myr, $>$ 200 pc) often dominate these types of studies. Such clusters frequently suffer from limiting magnitudes leading to an over-representation of high-mass stars. As high-mass stars disperse their disks earlier, the derived disk lifetimes apply best to high-mass stars rather than low-mass stars. Including only nearby clusters ($<$ 200 pc) minimizes the effect of limiting magnitude. In this case, the median disk lifetime of low-mass stars is with 5 -- 10 Myr, thus much longer than often claimed. The longer timescales provide planets ample time to form. How high-mass stars form planets so much faster than low-mass stars is the next grand challenges.