The Accretion Disc Dynamo in the Solar Nebula

TL;DR

This paper investigates the accretion disc dynamo in the solar nebula, highlighting the need for improved models to explain heating processes essential for chondrule formation, which current simulations do not adequately capture.

Contribution

It identifies limitations of existing MRI-driven dynamo simulations in explaining heating in the protosolar nebula and suggests the necessity for better dynamo models.

Findings

Current simulations do not meet heating constraints for chondrule formation.

The protosolar nebula's accretion processes require stronger, intermittent heating.

Existing models may underestimate energy release in accretion discs.

Abstract

The nearest accretion disc to us in space if not time was the protosolar nebula. Remnants of this nebula thus potentially offer unique insight into how discs work. In particular the existence of chondrules, which must have formed in the disc as small molten droplets, requires strong and intermittent heating of disc material. We argue that this places important constraints on the way gravitational energy is released in accretion discs, which are not met by current shearing--box simulations of MRI--driven dynamos. A deeper understanding of accretion energy release in discs may require a better model for these dynamos.