Relative importance of physical processes driving accretion–disk-mass dispersion

Determine the relative importance of internal and external physical processes, including internal and external photoevaporation, planet formation, dust evolution, dynamical interactions, and late-stage infall, in producing the observed dispersion in the mass accretion rate–disk mass relation for protoplanetary disks.

Background

The paper explains that the observed dispersion in the mass accretion rate–disk mass relation is only partly attributable to observational uncertainties and systematic effects. Physical processes operating within disks and their environments may also contribute, but the relative contribution of each process has not been established. This problem is central to understanding disk evolution and the origin of the broad range of inferred disk lifetimes.

References

A decisive question is whether regions of the same stellar age show a genuine spread in disk fractions as environmental variation in the replenishment supply predicts.

— Stellar age is not disk age  (2609.17046 - Kuffmeier et al., 15 Sep 2026) in Section 5, Conclusions

The relative importance of each process, however, remains an open question.

— X-shooter survey Across Regions and Ages to probe Disk Evolution (ARADE): Accretion properties in Orion A and their relation with disk masses  (2609.00938 - Piscarreta et al., 1 Sep 2026) in Section 1, Introduction

More complete samples from these two sub-clusters are required to confirm which scenario is more applicable.

— Disk survey in the Serpens star-forming region: Environmental effects in nearby star-forming regions  (2609.03759 - Tong et al., 3 Sep 2026) in Section 4.2, External photoevaporation in Serpens

It remains largely unknown, however, what is the combined effect of internal stellar irradiation and external FUV fields on the terrestrial planet-forming disk region ($\lesssim$\,10 au) across stellar masses.

— XUE. ProDiMo models of internally and externally irradiated planet-forming disks around 0.3-4.0 solar mass stars (The IRIS project I)  (2609.08621 - Frediani et al., 8 Sep 2026) in Abstract