AAS 200th meeting, Albuquerque, NM, June 2002
Session 32. Core-Collapse of Massive Stars: Supernovae and Gamma-Ray Bursts
Topical Session Oral, Tuesday, June 4, 2002, 8:30-10:00am, 10:45am-12:30pm, 2:00-3:30pm, 3:45-5:30pm, Ballroom C

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[32.08] Exploring the Neutrino-Driven Explosion Mechanism of Massive Stars

H.-T. Janka (Max-Planck-Institute for Astrophysics)

In this talk I attempt to present an unprejudiced discussion of our present understanding of neutrino-driven explosions and the requirements for achieving future progress in theoretical work. Neutrinos undoubtedly play a crucial role for the dynamics of stellar core collapse and the evolution of the supernova shock. They clearly dominate the energetics of neutron star formation, as splendidly confirmed by the neutrino detection in connection with Supernova 1987A. Unfortunately, we do not have observational support for the theoretical conception that neutrino energy deposition behind the shock is the ultimate cause for the explosion of ``typical'' supernovae.

Numerical simulations and analytic work, however, demonstrate that neutrino-driven explosions can be obtained for suitable conditions and reasonable combinations of relevant parameters. But the outcome of computer models depends sensitively on changes of the input physics as well as details of the numerical treatment. Discussing the neutrino-driven mechanism is therefore a quantitative problem, and conclusive answers are jeopardized by deficiencies in the numerical description and our still incomplete knowledge of the physical conditions and neutrino interactions in dense matter.

Refering to results from a new generation of core-collapse simulations which solve the Boltzmann equation for the neutrino transport, I will show that quantitatively meaningful models require the inclusion of general relativity and the accurate (but so far grossly approximated) treatment of neutrino reactions below the neutrinosphere. Advancement towards a standard supernova model requires multi-dimensional calculations to account for the effects of hydrodynamic instabilities. The latter cannot only decide about the viability of the neutrino-driven mechanism, but can also account for the anisotropies observed in the majority of ordinary massive star explosions.

Acknowledgments: This work was supported by the Sonderforschungsbereich 375 on ``Astroparticle Physics'' of the Deutsche Forschungsgemeinschaft and grants of computer time on the CRAY T90 and CRAY SV1ex of the John von Neumann Institute for Computing in Jülich.

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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.