  The discovery of decay products of a short-lived radioisotope (SLRI) in the
Allende meteorite led to the hypothesis that a supernova shock wave transported
freshly synthesized SLRI to the presolar dense cloud core, triggered its
self-gravitational collapse, and injected the SLRI into the core. Previous
multidimensional numerical calculations of the shock-cloud collision process
showed that this hypothesis is plausible when the shock wave and dense cloud
core are assumed to remain isothermal at ~10 K, but not when compressional
heating to ~1000 K is assumed. Our two-dimensional models (Boss et al. 2008)
with the FLASH2.5 adaptive mesh refinement (AMR) hydrodynamics code have shown
that a 20 km/sec shock front can simultaneously trigger collapse of a 1 solar
mass core and inject shock wave material, provided that cooling by molecular
species such as H2O, CO, and H2 is included. Here we present the results for
similar calculations with shock speeds ranging from 1 km/sec to 100 km/sec. We
find that shock speeds in the range from 5 km/sec to 70 km/sec are able to
trigger the collapse of a 2.2 solar mass cloud while simultaneously injecting
shock wave material: lower speed shocks do not achieve injection, while higher
speed shocks do not trigger sustained collapse. The calculations continue to
support the shock-wave trigger hypothesis for the formation of the solar
system, though the injection efficiencies in the present models are lower than
desired.
