The radial structure of protostellar accretion disks: influence of jets

TL;DR

This paper develops an analytical model for protostellar accretion disks that include the effects of jets, revealing structural differences from standard disks and providing formulas for observational and theoretical use.

Contribution

It introduces a new analytical framework for jet-emitting disks that accounts for jet torque, extending the standard accretion disk model to include jet effects.

Findings

JEDs have a significantly different structure from SADs.

Derived analytical expressions for disk properties in various opacity regimes.

Model can be used to test observationally and inform planet formation studies.

Abstract

The radial structure of accretion disks is a fundamental issue regarding star and planet formation. Many theoretical studies, focussing on different aspects such as e.g. disk emissivity or ionization, have been conducted in the context of the Standard Accretion Disk (SAD) model, where no jet is present. We wish to calculate the structure of YSO accretion disks in an approach that takes into account the presence of the protostellar jets. The radial structure of these Jet Emitting Disks (JED) should then be compared to that of standard accretion disks. The analytical treatment used in this work is very similar to that of standard accretion disks but is using the parameter space of Magnetised Accretion-Ejection Structures that include the jet torque on the underlying disk. In this framework, the analytical expressions of key quantities, such as mid-plane temperatures, surface densities or disk aspect ratio are derived. It is found that JEDs present a structure very different from the SADs and that can be observationally tested. The implications on planet formation in the inner regions of accretion disks are briefly discussed. We also supply sets of analytical formulae, valid in different opacity regimes, for the disk quantities. These expressions can be readily used for any work where the disk structure is needed as an input for the model.