Oral Presentation

Planet Formation in Warped Discs: Gravitational Instability and Misaligned Infall

Author(s): Sahl Rowther (University of Warwick), Josh Calcino (Tsinghua University), Richard Alexander (University of Leicester)

Presenter: Sahl Rowther (University of Warwick)

In their youth, protoplanetary discs are expected to be massive enough that their self-gravity drives the evolution of the disc. In this early phase, they are also more likely to be influenced by the star-forming environment. However, simulations of protoplanetary discs typically model isolated discs, neglecting the environment. In this talk, I will present my results showing how the star-forming environment plays a key role in shaping the evolution of young protoplanetary discs.

We perform three-dimensional smoothed particle hydrodynamics simulations to investigate the impact of misaligned infall on a gravitationally unstable protoplanetary disc. The interaction between the disc and the infalling gas does not occur equally across all radii. As infall impacts the outer disc first, it experiences stronger torques than the inner disc, resulting in a warped disc where the angular momentum vector of the disc varies with radius. The disc becomes warmer due to shock heating as infalling material impacts the disc, weakening the spiral arms driven by gravitational instability. However, infall also continuously increases the disc mass, gradually altering the local conditions and strengthening gravitational instabilities. Eventually, one of the spiral arms fragments, forming a planet by gravitational instability in a disc warped by misaligned infall.

We find that infall alters the expected signatures of gravitationally unstable discs by introducing asymmetries in scattered-light, continuum, and molecular line emission.