Overlap of planet formation with accretion outbursts or gravitational instability

Investigate whether planet formation occurs spatially or temporally concurrent with disk accretion outbursts or within regions of active gravitational instability, and determine how such environments modify growth processes.

Background

Protostellar disks can experience FU Ori-like outbursts and, especially at early times or large radii, can be self-gravitating. The author notes that these environments differ fundamentally and may alter coagulation, accretion, and migration, posing critical questions about timing and location of planet formation relative to such phenomena.

References

Open questions and problems that I would like to see resolved include, in no particular order: Does planet formation overlap spatially or temporally with disk accretion outbursts, or with regions of active gravitational instability? Either of these processes -- conventionally but not necessarily occurring mostly at early times -- lead to a fundamentally different environment for growth.

— Planet formation theory: an overview  (2412.11064 - Armitage, 2024) in Section “Some open questions”, Item 5

Understanding whether and under what conditions dust concentration and core formation remain viable in infall-driven discs is therefore a critical open question, with direct implications for the timescale and efficiency of planet formation during the earliest phase of disc evolution.

— Gravitational instability in planet-forming discs  (2609.05080 - Longarini et al., 4 Sep 2026) in Section 5.1.1, Theoretical perspective, p. 20