The Supernova Trigger and Meteoritic Components

Supernova Environment and Triggered Molecular Cloud Collapse: I have been studying the operation of the r-process in a core collapse supernova just after the large flux of neutrinos and antineutrinos has blown the presupernova envelope off the newly formed neutron star [1,2]. The hot (10 K) neutron star surface will emit a wind largely composed of neutrons, but these will only build up r-process products to about A = 80 (A is the mass number) [3]. However, if one now adds the effects of rotation and magnetic fields to this model, the collapse produces a disk accreting toward the neutron star, and the magnetic field is wrapped into a toroid by the differential rotation in the star, so that the increasing magnetic pressure in the equatorial plane generates an extrusion disk. Where these two flows meet a magnetically driven pair of jets will be formed surrounding and parallel to the rotation axis [1]. The material from both the accretion and extrusion flows enters the base of the jets and is ejected upwards at about half the speed of light, or about 140 MeV per nucleon [1]. The r-process takes place in the extrusion disk. The jets will blast their way through the expanding supernova envelope, mostly just depositing energy, but also causing extensive nuclear spallation for which there is evidence in solar system nuclidic abundances and in several meteoritic components [2]. I discuss here the observable effects in primitive solar system material when the supernova in question is the one that triggered the collapse of a molecular cloud core to form the primitive solar nebula.