Exploring the possibility of Peter Pan discs across stellar mass

TL;DR

This study investigates the longevity of primordial protoplanetary discs around stars of different masses, concluding that long-lived 'Peter Pan discs' are only feasible around low-mass M dwarf stars due to mass-dependent dispersal processes.

Contribution

The paper models how mass loss processes affect disc lifetimes across stellar masses, explaining the occurrence of long-lived discs primarily around M dwarfs.

Findings

Discs around stars ≤ 0.6 M⊙ can last up to 50 Myr.

Higher mass stars (> 0.8 M⊙) have shorter disc lifetimes due to stronger radiation effects.

Discs around stars up to 2 M⊙ can survive up to 15 Myr.

Abstract

Recently, several accreting M dwarf stars have been discovered with ages far exceeding the typical protoplanetary disc lifetime. These `Peter Pan discs' can be explained as primordial discs that evolve in a low-radiation environment. The persistently low masses of the host stars raise the question whether primordial discs can survive up to these ages around stars of higher mass. In this work we explore the way in which different mass loss processes in protoplanetary discs limit their maximum lifetimes, and how this depends on host star mass. We find that stars with masses $\lesssim$ 0.6 M$_\odot$ can retain primordial discs for $\sim$50 Myr. At stellar masses $\gtrsim$ 0.8 M$_\odot$, the maximum disc lifetime decreases strongly to below 50 Myr due to relatively more efficient accretion and photoevaporation by the host star. Lifetimes up to 15 Myr are still possible for all host star masses up to $\sim$2 M$_\odot$. For host star masses between 0.6 and 0.8 M$_\odot$, accretion ceases and an inner gap forms before 50 Myr in our models. Observations suggest that such a configuration is rapidly dispersed. We conclude that Peter Pan discs can only occur around M dwarf stars.