UC San Diego Researchers Advance Explanation for Star Formation

Projected density images resembling the inner structure of molecular clouds controlled by the turbulence that breaks the cloud into fragments, providing initial conditions for star formation. Simulation done using Kraken abnd Nautilus supercomputers at NICS. Image credit: A. Kritsuk, P. Padoan, R. Wagner, M. Norman, UC San Diego A newly published paper by three UC San Diego astrophysics researchers for the first time provides an explanation for the origin of three observed correlations between various properties of molecular clouds in the Milky Way galaxy known as Larson's Laws. The paper, called ' A Supersonic Turbulence Origin of Larson's Laws ', was published this month in the Monthly Notices of the Royal Astronomical Society, Great Britain's pre-eminent astronomy and astrophysics journal. Larson's Laws, named so by professors teaching the three principles from the seminal 1981 paper by Richard Larson, an Emeritus Professor of Astronomy at Yale, describes the observation-based relationships of the structure and supersonic internal motions of molecular clouds where stars form. The analysis by the UC San Diego researchers is based on recent observational measurements and data from six simulations of the interstellar medium, including effects of self-gravity, turbulence, magnetic field, and multiphase thermodynamics. The supercomputer simulations support a turbulent interpretation of Larson's relations, and the study concludes that there are not three independent Larson laws, but that all three correlations are due to the same underlying physics, i.e. the properties of supersonic turbulence.