Nuclear Neutrino Spectra in Late Stellar Evolution

¹ School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
² Collaborative Innovation Center of IFSA, Shanghai Jiao Tong University, Shanghai 200240, China
³ Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
⁴ Department of Physics, University of California, San Diego La Jolla, CA 92093, USA

^* e-mail: wendell.misch@gmail.com
^** e-mail: sunyang@sjtu.edu.cn
^*** e-mail: gfuller@ucsd.edu

Published online: 16 May 2018

Abstract

Neutrinos are the principle carriers of energy in massive stars, beginning from core carbon burning and continuing through core collapse and after the core bounce. In fact, it may be possible to detect neutrinos from nearby pre-supernova stars. Therefore, it is of great interest to understand the neutrino energy spectra from these stars. Leading up to core collapse, beginning around core silicon burning, nuclei become dominant producers of neutrinos, particularly at high neutrino energy, so a systematic study of nuclear neutrino spectra is desirable. We have done such a study, and we present our sd-shell model calculations of nuclear neutrino energy spectra for nuclei in the mass number range A = 21 – 35. Our study includes neutrinos produced by charged lepton capture, charged lepton emission, and neutral current nuclear deexcitation. Previous authors have tabulated the rates of charged current nuclear weak interactions in astrophysical conditions, but the present work expands on this not only by providing neutrino energy spectra, but also by including the heretofore untabulated neutral current de-excitation neutrino pairs.