The effect of a stellar magnetic variation on the jet velocity

TL;DR

This paper investigates how small changes in the inner disk-wind radius, potentially caused by stellar magnetic field variations, can lead to jet velocity fluctuations that produce observable knots in stellar jets.

Contribution

It demonstrates that minor variations in the inner disk-wind radius can generate jet knots, linking magnetic field changes to jet structure formation.

Findings

Small variations in inner disk-wind radius cause significant jet velocity changes.

Magnetic field variations may influence the inner disk-wind radius.

Generated jet knots match observed periodicity and structure.

Abstract

Stellar jets are normally constituted by chains of knots with some periodicity in their spatial distribution, corresponding to a variability of order of several years in the ejection from the protostar/disk system. A widely accepted theory for the presence of knots is related to the generation of internal working surfaces due to variations in the jet ejection velocity. In this paper we study the effect of variations in the inner disk-wind radius on the jet ejection velocity. We show that a small variation in the inner disk-wind radius produce a variation in the jet velocity large enough to generate the observed knots. We also show that the variation in the inner radius may be related to a variation of the stellar magnetic field.