The antesonic condition for the explosion of corecollapse supernovae  II. Rotation and turbulence
Abstract
In the problem of steady free fall on to a standing shockwave around a central mass, the 'antesonic' condition limits the regime of stable accretion to $c_T^2/v_\mathrm{esc}^2\le 3/16$ , where c_{T} is the isothermal sound speed in the subsonic postshock flow, and v_{esc} is the escape velocity at the shock radius. Above this limit, it is impossible to satisfy both the Euler equation and the shock jump conditions, and the system transitions to a wind. This physics explains the existence of a critical neutrino luminosity in steadystate models of accretion in the context of corecollapse supernovae. Here, we extend the antesonic condition to flows with rotation and turbulence using a simple onedimensional formalism. Both effects decrease the critical postshock sound speed required for explosion. While quite rapid rotation is required for a significant change to the critical condition, we show that the level of turbulence typically achieved in supernova simulations can greatly impact the critical value of $c_T^2/v_\mathrm{esc}^2$ . A core angular velocity corresponding to a millisecond rotation period after contraction of the protoneutron star results in only a ∼5 per cent reduction of the critical curve. In contrast, nearsonic turbulence with specific turbulent kinetic energy $K/c_T^2=0.51$ , leads to a decrease in the critical value of $c_T^2/v_{\rm esc}^2$ by ∼20 to 40 per cent. This analysis provides a framework for understanding the role of postshock turbulence in instigating explosions in models that would otherwise fail and helps explain why multidimensional simulations explode more easily than their onedimensional counterparts.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 April 2021
 DOI:
 10.1093/mnras/stab286
 arXiv:
 arXiv:2009.04478
 Bibcode:
 2021MNRAS.502.4125R
 Keywords:

 accretion;
 accretion discs;
 hydrodynamics;
 shock waves;
 supernovae: general;
 Astrophysics  High Energy Astrophysical Phenomena
 EPrint:
 Submitted to MNRAS. 13 pages, 5 figures