The impact of asymmetric neutrino emissions on nucleosynthesis in core-collapse supernovae II – progenitor dependences

Abstract

ABSTRACT We investigate the impact of asymmetric neutrino emissions on explosive nucleosynthesis in core-collapse supernovae (CCSNe) of progenitors with a mass range of 9.5–25 M⊙. We perform axisymmetric, hydrodynamic simulations of the CCSN explosion with a simplified neutrino transport, in which anticorrelated dipolar emissions of νe and ${\bar{\nu }}_{\rm e}$ are imposed. We then evaluate abundances and masses of the CCSN ejecta in a post-processing manner. We find that the asymmetric ν-emission leads to the abundant ejection of p- and n-rich matter in the high-νe and -${\bar{\nu }}_{\rm e}$ hemispheres, respectively. It substantially affects the abundances of the ejecta for elements heavier than Ni regardless of progenitors, although those elements lighter than Ca are less sensitive. Based on these results, we calculate the initial mass function-averaged abundances of the CCSN ejecta with taking into account the contribution from Type Ia SNe. For $m_{\rm asy} = 10/3{{\ \rm per\ cent}}$ and $10{{\ \rm per\ cent}}$, where masy denotes the asymmetric degree of the dipole components in the neutrino emissions, the averaged abundances for elements lighter than Y are comparable to those of the solar abundances, whereas those of elements heavier than Ge are overproduced in the case with $m_{\rm asy} \ge 30{{\ \rm per\ cent}}$. Our result also suggests that the effect of the asymmetric neutrino emissions is imprinted in the difference of abundance ratio of [Ni/Fe] and [Zn/Fe] between the high-νe and -${\bar{\nu }}_{\rm e}$ hemispheres, indicating that the future spectroscopic X-ray observations of a CCSN remnant will bring evidence of the asymmetric neutrino emissions if exist.