English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We present the results of eighteen magnetohydrodynamical calculations of thecollapse of a molecular cloud core to form a protostar. Some calculationsinclude radiative transfer in the flux-limited diffusion approximation whileothers employ a barotropic equation of state. We cover a wide parameter space,with mass-to-flux ratios ranging from $\mu = 5$ to $20$; initial turbulentamplitudes ranging from a laminar calculation (i.e. where the Mach number,$\mathscr{M} = 0$) to transonic $\mathscr{M} = 1$; and initial rotation ratesfrom $\beta_\mathrm{rot} = 0.005$ to $0.02$. We first show that using aradiative transfer scheme produces warmer pseudo-discs than the barotropicequation of state, making them more stable. We then `shake' the core byincreasing the initial turbulent velocity field, and find that at all threemass-to-flux ratios transonic cores are weakly bound and do not producepseudo-discs; $\mathscr{M} = 0.3$ cores produce very disrupted discs; and$\mathscr{M} = 0.1$ cores produce discs broadly comparable to a laminar core.In our previous paper (arXiv:1701.08741), we showed that a pseudo-disc coupledwith sufficient magnetic field is necessary to form a bipolar outflow. Here weshow that only weakly turbulent cores exhibit collimated jets. We finally takethe $\mathscr{M} = 1.0$, $\mu = 5$ core and `stir' it by increasing the initialangular momentum, finding that once the degree of rotational energy exceeds theturbulent energy in the core the disc returns, with a corresponding (thoughslower), outflow. These conclusions place constraints on the initial mixturesof rotation and turbulence in molecular cloud cores which are conducive to theformation of bipolar outflows early in the star formation process.

Shaken and stirred: the effects of turbulence and rotation on disc and outflow formation during the collapse of magnetised molecular cloud cores