Magnetic waves and Stellar Formation:

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https://phys.org/news/2018-09-magnetic-chaos-star-forming-clouds.html

Magnetic waves create chaos in star-forming clouds

September 13, 2018, University of Texas McDonald Observatory

New research by Stella Offner, assistant professor of astronomy at The University of Texas at Austin, finds that magnetic waves are an important factor driving the process of star formation within the enormous clouds that birth stars. Her research sheds light on the processes that are responsible for setting the properties of stars, which in turn affects the formation of planets orbiting them, and, ultimately, life on those planets. The research is published in the current issue of the journal Nature Astronomy.

Offner used a supercomputer to make models of the multitude of processes happening inside a cloud where stars are forming, in an effort to sort out which processes lead to which effects.

Read more at: https://phys.org/news/2018-09-magnetic-chaos-star-forming-clouds.html#jCp

 

the paper:

https://www.nature.com/articles/s41550-018-0566-1

Turbulent action at a distance due to stellar feedback in magnetized clouds:

 

Abstract:

A fundamental property of molecular clouds is that they are turbulent1, but how this turbulence is generated and maintained is unknown. One possibility is that stars forming within the cloud regenerate turbulence via their outflows, winds and radiation (‘feedback’)2. However, disentangling motions created by feedback from the initial cloud turbulence is challenging. Here, we confront the relationship between stellar feedback and turbulence by identifying and separating the local and global impact of stellar winds. We analyse magnetohydrodynamic simulations in which we track wind material as it interacts with the ambient cloud. By distinguishing between launched material, gas entrained by the wind and pristine gas we show energy is transferred away from the sources via magnetic waves excited by the expanding wind shells. This action at a distance enhances the fraction of stirring motion compared with compressing motion and produces a flatter velocity power spectrum. We conclude that stellar feedback accounts for significant energy transfer within molecular clouds—an impact enhanced by magnetic waves, which have previously been neglected by observations. Overall, stellar feedback can partially offset global turbulence dissipation.