Supernova injection of short-lived radionuclides into the presolar cloud: A feasibility study

Meteorite inclusions show that the early solar system was radioactive with species of short lifetimes compared to the formation time of the solar system. Transporting the radioactive material from the creation site to the formation site of the sun was expected to take enough time that these species should have decayed to nonexistence. Some special series of events seems necessary to speed the process along. Cameron & Truran (1977) suggested that the source of these short-lived radionuclides could have been a supernova. Numerical hydrodynamic studies have shown that slow shockwaves can inject material into a small, dense cloud core. Most stars are not born in lone dense cores. Thus any core that might have become the solar system was probably shrouded with an envelope that the ejecta from supernova would have had to penetrate along with the intervening interstellar medium. We present numerical hydrodynamic studies using Zeus-2D investigating how a supernova can inject its material into a moderately dense molecular cloud. We model a self-similar explosion colliding with a spherical cloud and examine the results for injection. We have modified Zeus-2D by adding three tracking dyes and changing the effective adiabatic index of the fluid in response to the shock-cloud collision. We find that if the effective adiabatic index of the gas is less than 5/3 then injection can occur, and we describe the basics of the mechanism by which this occurs.