Control of star formation by supersonic turbulence

TLDR

Star formation in galaxies has long been attributed to gravity and magnetic support, but recent observations and simulations suggest supersonic turbulence may be the dominant regulator. This review proposes a turbulence‑driven theory of star formation. The authors analyze how turbulence governs star formation across local and galactic scales. Supersonic turbulence globally supports clouds yet creates localized density peaks that trigger isolated, inefficient star formation, whereas its absence leads to efficient, clustered star formation. Abstract abbreviated.

Abstract

Understanding the formation of stars in galaxies is central to much of modern astrophysics. For several decades it has been thought that stellar birth is primarily controlled by the interplay between gravity and magnetostatic support, modulated by ambipolar diffusion. Recently, however, both observational and numerical work has begun to suggest that support by supersonic turbulence rather than magnetic fields controls star formation. In this review we outline a new theory of star formation relying on the control by turbulence. We demonstrate that although supersonic turbulence can provide global support, it nevertheless produces density enhancements that allow local collapse. Inefficient, isolated star formation is a hallmark of turbulent support, while efficient, clustered star formation occurs in its absence. The consequences of this theory are then explored for both local star formation and galactic scale star formation. (ABSTRACT ABBREVIATED)