Warping Away Gravitational Instabilities in Protoplanetary Discs

TL;DR

This study uses 3D simulations to show that warps in young, self-gravitating protoplanetary discs heat the disc and suppress spiral structures, aligning theoretical models with observations of mostly axisymmetric discs.

Contribution

It demonstrates that warps in protoplanetary discs can stabilize them against gravitational instabilities, explaining the lack of observed spiral structures in young discs.

Findings

Warps heat the disc, reducing gravitational instability.

Warped discs appear more axisymmetric, matching observations.

Suppression of spiral structures due to warping.

Abstract

We perform 3D SPH simulations of warped, non-coplanar gravitationally unstable discs to show that as the warp propagates through the self-gravitating disc, it heats up the disc rendering it gravitationally stable. Thus losing their spiral structure and appearing completely axisymmetric. In their youth, protoplanetary discs are expected to be massive and self-gravitating, which results in non-axisymmetric spiral structures. However recent observations of young protoplanetary discs with ALMA have revealed that discs with large-scale spiral structure are rarely observed in the midplane. Instead, axisymmetric discs with some also having ring & gap structures are more commonly observed. Our work invloving warps, non-coplanar disc structures that are expected to commonly occur in young discs, potentially resolves this discrepancy between observations and theoretical predictions. We demonstrate that they are able to suppress the large-scale spiral structure of self-gravitating protoplanetary discs.