Dynamics of shock propagation and nucleosynthesis conditions in O-Ne-Mg core supernovae

• Published in: Astronomy and astrophysics (Berlin) Vol. 485; no. 1; pp. 199 - 208
• Main Authors: Janka, H.-Th, Müller, B., Kitaura, F. S., Buras, R.
• Format: Journal Article
• Language: English
• Published: Les Ulis EDP Sciences 01.07.2008
• Subjects: abundances; Astronomy; Earth, ocean, space; Exact sciences and technology; hydrodynamics; nuclear reactions; nucleosynthesis; supernovae: general; Spherical symmetry; Shock layer; nuclear reactions, nucleosynthesis, abundances; Supernovae; Nucleosynthesis; Digital simulation; Neutrons; Abundance; Entropy; hydrodynamics; r process; Axial symmetry; supernovae: general; Necessary condition; Dynamics; Hydrodynamic model
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361:20079334

It has been recently proposed that the shocked surface layers of exploding O-Ne-Mg cores provide the conditions for r-process nucleosynthesis, because their rapid expansion and high entropies enable heavy r-process isotopes to form even in an environment with very low initial neutron excess of the matter. We show here that the most sophisticated available hydrodynamic simulations (in spherical and axial symmetry) do not support this new r-process scenario because they fail to provide the necessary conditions of temperature, entropy, and expansion timescale by significant factors. This suggests that, either the formation of r-process elements works differently than suggested by Ning et al. (ApJ, 667, L159, NQM07), or that some essential core properties with influence on the explosion dynamics might be different from those predicted by Nomoto's progenitor model.