Supernovae explosions induced by pair production instability

<p>Stars with a core mass greater than about 30 M_⊙ become dynamically unstable due to electron-positron pair production when their central temperature reaches 1.5-2.0 x 10⁹ ⁰K. The collapse and subsequent explosion of stars with core masses of 45, 52, and 60 M_⊙ is calculated. The range of the final velocity of expansion (3,400 – 8,500 km/sec) and of the mass ejected (1 – 40 M_⊙) is comparable to that observed for type II supernovae.</p> <p>An implicit scheme of hydrodynamic difference equations (stable for large time steps) used for the calculation of the evolution is described.</p> <p>For fast evolution the turbulence caused by convective instability does not produce the zero entropy gradient and perfect mixing found for slower evolution. A dynamical model of the convection is derived from the equations of motion and then incorporated into the difference equations. </p>