We examine explosive nucleosynthesis during neutrino-driven, aspherical supernova
(SN) explosion
aided by standing accretion shock instability, based on two-dimensional hydrodynamic
simulations
of the explosion of 15-40$M_\odot$ stars with zero metallicity.
The magnitude and asymmetry of the explosion energy are estimated with the simulations,
for a given set of neutrino luminosities and temperatures.
By post-processing calculations with a large nuclear reaction network,
we have evaluated abundances and masses of ejecta from the aspherical SNe.
We find that the evaluated abundance patterns are similar to those observed in
extremely metal poor stars (Cayrel et al. 2004, Lai et al. 2008),
as shown in the spherical models of Tominaga et al. (2007) and Heger \& Woosley
(2008) and
in the two-dimensional models of Joggerst et al. (2010),
although in their models, the explosion is manually and spherically initiated by
means of a thermal bomb or a piston.
Sc and Co, which are underproduced in the two-dimensional models of Joggerst et al.
(2010), are appropriately produced in our models.
Hypernovae may not be required to reproduce the observed abundance patterns.
No models in our simulations, however, can reproduce large [C,N,O/Mg] (> 1) observed
in two hyper metal-poor stars. |