Institute for Advanced Study Astrophysics Seminar

The ubiquity of substructures in protoplanetary discs has opened debate regarding the alignment of planet formation timescales with protostellar disc evolution. Under the hypothesis of the planetary interpretation, a robust conclusion is that a substantial part of the planet formation process must overlap with the time when protostellar discs are likely to be young and, possibly, gravitationally unstable. Historically, gravitational instability has been proposed as a pathway for planetary formation. However, it lost favour due to the higher likelihood of forming stellar companions rather than planets. Nevertheless, recently, this scenario has gained new interest, when the synergy between gravitational instability and dust dynamics is considered.

In this talk, I will discuss the interplay between dust dynamics and gravitational instability. Gravitational instability is responsible for the formation of a large scale spiral structure, that efficiently traps dust. There, the dust concentration can be so high that it becomes unstable, possibly collapsing into Earth-mass objects. We analytically characterise this behaviour, and we confirm it through numerical simulations, showing that planetary cores at large radii can be efficiently formed in young protostellar discs.