Turbulence and the characteristics of circumstellar discs

Abstract

We investigate the properties of circumstellar discs (CDs) produced in hydrodynamical simulations of gravoturbulent core collapse considering Kolmogorov and Burger-type turbulence. We report that massive discs are more prevalent in the Kolmogorov regime than for Burger-type turbulence. A significant number of discs are formed with a radius of $\sim$ 15 au in both cases. However, the number of extended discs with radii $>$ 15 au is significantly larger in case of Kolmogorov turbulence. The two regimes of turbulence, in general, yield disc radii in the ranges of 7 au $-$ 30 au, and 13 au $-$ 39 au, respectively. The corresponding ranges of the disc masses are 30.37 $M_{\rm Jup}$ $-$ 0.92 M$_{\odot}$, and 2.09 $M_{\rm Jup}$ $-$ 0.13 M$_{\odot}$, respectively. Moreover, the ratio $M_{\rm disc}$/$M_{\rm star}$ is higher in models of Kolmogorov-type turbulence than in models of Burgers-type turbulence. We do not find any correlation between $R_{\rm disc}$ and $M_{\rm disc}$ over the explored range of initial temperatures (8 K $-$ 14 K) and the type of turbulence. Also, for these initial thermal variations, the turbulent circumstellar disc structures do not exhibit signs of turbulent diffusion. Nonetheless, both sub and supersonic velocity dispersions cause variations in the specific angular momentum (AM) of infalling gas, especially for CDs with radii $\sim$ 16 au $-$ 21 au. The radial profiles of CDs do not correlate with the initial conditions.