Explosive nucleosynthesis of ultra-stripped Type Ic supernovae: application to light trans-iron elements

We investigate the explosive nucleosynthesis during two dimensional neutrino-driven explosion of ultra-stripped Type Ic supernovae evolved from 1.45 and 1.5 M${}_{\odot }$ CO stars. These supernovae explode with the explosion energy of $\sim {10}^{50}$ erg and release $\sim 0.1$ M${}_{\odot }$ ejecta. The light trans-iron elements Ga-Zr are produced in the neutrino-irradiated ejecta. The abundance distribution of these elements has a large uncertainty because of the uncertainty of the electron fraction of the neutrino-irradiated ejecta. The yield of the elements will be less than 0.01 M${}_{\odot }$. Ultra-stripped supernova and core-collapse supernova evolved from a light CO core can be main sources of the light trans-iron elements. They could also produce neutron-rich nuclei ${}^{48}$Ca. The ultra-stripped supernovae eject ${}^{56}$Ni of $\sim$ 0.006

• 0.01 M${}_{\odot }$. If most of neutrino-irradiated ejecta is proton-rich, ${}^{56}$Ni will be produced more abundantly. The light curves of these supernovae indicate sub-luminous fast decaying explosion with the peak magnitude of about $-15$ - $-16$. Future observations of ultra-stripped supernovae could give a constraint to the event rate of a class of neutron star mergers.