Type Ib/Ic supernovae: effect of nickel mixing on the early-time color evolution and implications for the progenitors

Understand

We investigate the effect of mixing of radioactive nickel ($^{56}$Ni) on the early-time color evolution of Type Ib and Ic supernovae (SNe Ib/Ic) using multi-group radiation hydrodynamics simulations.

• We consider both helium-rich and helium-poor progenitors.
• Mixing of $^{56}$Ni is parameterized using a Gaussian distribution function.
• We find that the early-time color evolution with a weak $^{56}$Ni mixing is characterized by three different phases: initial rapid reddening, blueward evolution due to the delayed effect of $^{56}$Ni heating, and redward evolution thereafter until the transition to the nebular phase.