%0 Journal Article
%T -Process Nucleosynthesis in MHD Jet Explosions of Core-Collapse Supernovae
%A Motoaki Saruwatari
%A Masa-aki Hashimoto
%A Ryohei Fukuda
%A Shin-ichiro Fujimoto
%J Journal of Astrophysics
%D 2013
%R 10.1155/2013/506146
%X We investigate the -process nucleosynthesis during the magnetohydrodynamical (MHD) explosion of a supernova in a helium star of 3.3£¿ , where effects of neutrinos are taken into account using the leakage scheme in the two-dimensional (2D) hydrodynamic code. Jet-like explosion due to the combined effects of differential rotation and magnetic field is able to erode the lower electron fraction matter from the inner layers. We find that the ejected material of low electron fraction responsible for the -process comes out from just outside the neutrino sphere deep inside the Fe-core. It is found that heavy element nucleosynthesis depends on the initial conditions of rotational and magnetic fields. In particular, the third peak of the distribution is significantly overproduced relative to the solar system abundances, which would indicate a possible -process site owing to MHD jets in supernovae. 1. Introduction Study of the -process has been developed considerably keeping pace with the terrestrial experiments of nuclear physics far from the stability line of nuclides [1]. In particular, among the three peaks, which correspond to the elements of , , and , in the abundance pattern for the solar system -elements, the transition from the second to third peak elements has been stressed by nuclear physicists [2]. Although supernovae could be one of the astrophysical sites of the -process [2, 3], explosion mechanism is not still completely resolved, where supernova explosions are originated from the gravitational collapse of massive stars of £¿ [4, 5]. However it is unclear whether neutron-rich elements could be ejected or not during the shock wave propagation. As far as the one-dimensional calculations, almost all realistic numerical simulations concerning the collapse-driven supernovae of £¿ have failed to explode the outer layer above the Fe-core due to drooping of the energetic shock wave propagation [6, 7]. Although there exist calculations for 8 and 11£¿ stars to explode, the explosion energies are very weak [8¨C15]. Therefore, a plausible site/mechanism of the -process has not yet been clarified. On the other hand, models of magnetorotational explosion (MRE) for core-collapse supernovae have been presented as a supernova mechanism [16¨C19] since both rapid rotations and/or strong magnetic fields could be resulted for neutron stars after the explosions. Furthermore, MRE with a realistic magnetic field configuration has been investigated [20¨C22]. In their series of papers, it has been shown that magnetorotational instability plays a critical role concerning the
%U http://www.hindawi.com/journals/jas/2013/506146/