On the Nucleosynthesis in Accretion-Induced Collapse of White Dwarfs

Abstract

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 $\sim 10^{53}$ erg s${}^{-1}$, comparable to that of a core-collapse supernova (CCSN), is emitted. The ejecta mass of AIC could be up to $\sim 10^{-2}$ M${}_{\odot }$, and the first neutron-capture peak elements (Sr, Y, and Zr) could be abundantly synthesized, with an overproduction of $\sim 10^6$ relative to the solar abundances. The yield of ${}^{56}\text{Ni}$ could be up to at most $\sim 10^{-3}$ 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 $\sim 10\%$ relative to those of CCSNe and Type Ia SNe.

13 pages, 9 figures