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H.A.T. Vanhala (Challenger Center for Space Science Education)
According to the hypothesis of the triggered origin of the solar system, the formation of our planetary system was initiated by the impact of an interstellar shock wave on a molecular cloud core. The shock wave originated from a nearby explosive stellar event and carried with it nucleosynthesis products from the stellar source. In addition to causing the molecular cloud core to collapse earlier than it would have otherwise, the shock wave also deposited some of the freshly synthesized nuclides into the collapsing system. These short-lived radioactivities were then incorporated into the first solar system solids, in this manner leaving a record of the event in the meteoritic material.
Numerical calculations investigating the processes involved in the interaction between an interstellar shock wave and a molecular cloud core have confirmed the viability of the hypothesis. The next stage of the investigation, reported here, concentrates on examining the process through which the radioactivities are injected into the forming solar system. For this purpose, a new version of EVH-1 (Enhanced Virginia Hydrodynamics) simulation code is being developed. The code will combine the best properties of the simulation methods used in the previous calculations, by allowing for high-resolution calculations using realistic thermodynamics and accurate shock handling. The simulations performed with the new code address the nature of the instabilities which were detected to develop at the surface of the compressed molecular cloud core by the previous calculations and which make it possible for radioactivities carried by the shock wave to be injected into the forming solar system.
This work was supported by NASA Origins of Solar Systems grant.
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.