Triggering Collapse of the Presolar Dense Cloud Core and Injecting Short-Lived Radioisotopes with a Shock Wave. I. Varied Shock Speeds - Astrophysics > Earth and Planetary AstrophysicsReportar como inadecuado




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Abstract: The discovery of decay products of a short-lived radioisotope SLRI in theAllende meteorite led to the hypothesis that a supernova shock wave transportedfreshly synthesized SLRI to the presolar dense cloud core, triggered itsself-gravitational collapse, and injected the SLRI into the core. Previousmultidimensional numerical calculations of the shock-cloud collision processshowed that this hypothesis is plausible when the shock wave and dense cloudcore are assumed to remain isothermal at ~10 K, but not when compressionalheating to ~1000 K is assumed. Our two-dimensional models Boss et al. 2008with the FLASH2.5 adaptive mesh refinement AMR hydrodynamics code have shownthat a 20 km-sec shock front can simultaneously trigger collapse of a 1 solarmass core and inject shock wave material, provided that cooling by molecularspecies such as H2O, CO, and H2 is included. Here we present the results forsimilar calculations with shock speeds ranging from 1 km-sec to 100 km-sec. Wefind that shock speeds in the range from 5 km-sec to 70 km-sec are able totrigger the collapse of a 2.2 solar mass cloud while simultaneously injectingshock wave material: lower speed shocks do not achieve injection, while higherspeed shocks do not trigger sustained collapse. The calculations continue tosupport the shock-wave trigger hypothesis for the formation of the solarsystem, though the injection efficiencies in the present models are lower thandesired.



Autor: Alan P. Boss, Sandra A. Keiser, Sergei I. Ipatov, Elizabeth A. Myhill, Harri A. T. Vanhala

Fuente: https://arxiv.org/







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