Active-Sterile Neutrino Oscillations in Neutrino-driven Winds: Implications for Nucleosynthesis

A protoneutron star produced in a core-collapse supernova (CCSN) drives a wind by its intense neutrino emission. We implement active-sterile neutrino oscillations in a steady-state model of this neutrino-driven wind to study their effects on the dynamics and nucleosynthesis of the wind in a self-consistent manner. Using vacuum mixing parameters indicated by some experiments for a sterile ν _s of ∼1 eV in mass, we observe interesting features of oscillations due to various feedback. For the higher ν _s mass values, we find that oscillations can reduce the mass-loss rate and the wind velocity by a factor of ∼1.6-2.7 and change the electron fraction critical to nucleosynthesis by a significant to large amount. In the most dramatic cases, oscillations shift nucleosynthesis from dominant production of ⁴⁵Sc to that of ⁸⁶Kr and ⁹⁰Zr during the early epochs of the CCSN evolution.