Are jets rotating at the launching?

TL;DR

The paper argues that observed Doppler asymmetries in young stellar object jets are due to interactions with circumstellar gas, not jet rotation, challenging previous claims and suggesting a different jet launching mechanism involving disk dynamos.

Contribution

It critically examines claims of jet rotation in YSOs, providing evidence that such rotation is much slower than previously thought and proposing a new jet launching model.

Findings

Doppler asymmetries are caused by jet-gas interactions.

Jets' rotation velocities are much lower than claimed.

Jets likely launched by disk dynamos similar to solar flares.

Abstract

I argue that the Doppler shift asymmetries observed in some young stellar object (YSO) result from the interaction of the jets with the circumstellar gas, rather than from jets' rotation. The jets do rotate, but at a velocity much below claimed values. During the meeting I carefully examined new claims, and found problems with the claimed jets' rotation. I will challenge any future observation that will claim to detect jet rotation in YSOs that requires the jets (and not a wind) to be launched from radii much larger than the accreting stellar radius. I conclude that the most likely jets' launching mechanism involves a very efficient dynamo in the inner part of the accretion disk, with jets' launching mechanism that is similar to solar flares (coronal mass ejection).