Ph.D Thesis


Ph.D StudentOded Papish
SubjectExpel of Gravitationally Bound Mass by Fast Jets from
Compact Objects
DepartmentDepartment of Physics
Supervisor Full Professors Soker Noam
Full Thesis textFull thesis text - English Version


Abstract

The explosion mechanism of core-collapse supernovae is one of the main open problems in stellar astrophysics. In this work we build a new model to explain the explosion mechanism of core-collapse supernovae. Our model, the Jittering-Jets model, is based on jets lunched from a newly born neutron star that change their direction and as a result inflate hot bubbles that explode the star. In our research we study this model both analytically and numerically using sophisticated multidimensional hydrodynamical simulations. We find that jets with typical parameters, i.e., velocity of 100,000 km s-1 and efficiency of 10\% of the accretion energy, can indeed explode the star with the desired  1051 of energy if jets do exist during the collapse. Our simulations show the existence of a negative feedback mechanism. The jets expel the gas around them in a way that prevents further accretion from all directions, including perpendicular to the jets direction, and as a result terminates jets launching episodes. We also study the r-process in the hot bubbles inflated by the jets and find that part of the r-process elements in nature might be explain by our model. One farther result is an analytically upper bound on the explosion energy in the delayed-neutrino mechanism for core-collapse supernovae. We find that the delayed-neutrino mechanism can lead in the most optimistic scenario to a weak explosion and so it cannot be the main channel for core-collapse supernovae._____________________________________________________________________________