Moving mesh simulations of star forming cores in magneto-gravo-turbulence

Philip Mocz (Harvard CfA) - November 21, 2016 at 12:10 pm

Star formation occurs in midst of a contest between self-gravity, turbulent pressure, and the magnetic field. In this talk, I will discuss the role of the magnetic field and under what conditions the cloud cores that form inherit large-scale field morphologies or are governed by cloud turbulence. I describe a new moving mesh constrained transport numerical method to solve the magnetohydrodyanmics equations. The moving mesh allows simulations to resolve gravitational collapse over orders of magnitude in dynamic range. I will present a range of simulations of parsec scale supersonic, turbulent molecular clouds, self-consistently resolving star formation down to a few AU scales (relevant for future ALMA observations). Core properties are found to be largely independent of the mean-field strength in the cloud, as long as turbulent pressure dominates the magnetic pressure. In this regime, collapse is approximately isotropic with B proportional to rho^(2/3) due to flux freezing, with turbulent field morphology uncorrelated with the large-scale field. In the strongly magnetized case, collapse is anisotropic with B proportional to rho^(1/2) and the field has a simple hourglass morphology aligned with the large-scale field. Different observations suggests that star formation in the interstellar medium may be occurring in both regimes.

The seminar will be held in 131A Campbell Hall.

Return to seminar schedule