On the Nucleosynthesis in Accretion-Induced Collapse of White Dwarfs

It has long been hypothesized that accretion-induced collapse (AIC) of white dwarfs contribute to heavy chemical elements production in the universe. We present one-dimensional neutrino-radiative hydrodynamic simulations of AIC followed by post-processing nucleosynthesis calculations of the ejecta. A proto-neutron star is formed after the AIC, and a neutrino burst with peak luminosity $\sim10^{53}$ erg s$^{-1}$, comparable to that of a core-collapse supernova (CCSN), is emitted. The ejecta mass of AIC could be up to $\sim10^{-2}$ M$_\odot$, and the first neutron-capture peak elements (Sr, Y, and Zr) could be abundantly synthesized, with an overproduction of $\sim10^{6}$ relative to the solar abundances. The yield of $^{56}\text{Ni}$ could be up to at most $\sim10^{-3}$ M$_\odot$, suggesting that the electromagnetic light curve associated with AIC is at least $2$ orders dimmer than those associated with Type Ia supernovae (Type Ia SN). The inferred upper bound of AIC event rate, from nucleosynthesis calculations, is at most $\sim10\,\%$ relative to those of CCSNe and Type Ia SNe.