Seminario DAS: The role of self-gravity in protoplanetary discs

Speaker: Dr. Cristiano Longarini
Affiliation: Cambridge University

Abstract: Protoplanetary discs are the link between stars and planet: they form with the star, and they are the environments where planet formation takes place. ALMA observations show that planet formation is ubiquitous, and occurs very early in the disc lifetime, when the disc is still massive. In such massive environments, gravitational instabilities are likely to occur, playing a crucial role in disc evolution. In this seminar, I will discuss the kinematical and dynamical effects of self-gravity and gravitational instability in protoplanetary discs. From a kinematical perspective, disc self-gravity alters the equilibrium state, producing a super-Keplerian rotation curve. Measuring this deviation allows us to constrain key properties of protoplanetary discs, such as their mass. I will present the results of the exoALMA large program. Secondly, I will explore the process of planet formation in gravitationally unstable discs. Specifically, I will highlight how the interplay with dust dynamics enables the formation of planetary cores via dust collapse in the outer disc regions. This mechanism bypasses the planetesimal formation barrier within the core accretion model of planet formation. I will present hydrodynamical simulations demonstrating dust collapse in gas spiral arms and examine the early evolution of the resulting planetary cores.