The ²⁶Al Production of the ν _e -process in the Explosion of Massive Stars

Abstract

The core collapses of massive stars at the ends of their lives will produce powerful streams of neutrinos, which provide an important contribution to the 26Al yield during the explosion stage. In this work, the contribution of the process 26 Mg ( ν e , e − ) 26 Al to the radioactive 26Al in the Milky Way is studied based on a simple model. By combining the calculation of the neutrino-nucleus cross section and some hypotheses about core-collapse supernova explosions, the ratio of 26Al and 26Mg of the ν e -process is estimated. An analytical relationship between the 26Mg yield and the initial mass and metallicity of massive stars is then obtained, making it easy to estimate the 26Mg and 26Al yields analytically. Due to the simplicity of the model, we can move away from complex calculations and into a careful study of the effects of some important factors, such as the radius of the O/Ne shell, the shock velocity, the neutrino spectrum, the Galactic mass and metallicity distribution, and so on. The uncertainties of the 26Al yield contributed from these factors are discussed in detail. This study will facilitate an intuitive understanding of the buried implicit assumptions in previous studies.

Influence of Neutrino–Nuclear Reactions on the Abundance of 74Se

“…If the shock wave velocity is slower and arrives later, more of the 74 As will be produced with a more powerful neutrino flux. There will be more 74 As produced if the shock velocity is as low as possible; however, too low a shock velocity may cause the explosion to fail (Li & Li 2022). By analyzing the abundance of 74 Se contributed by the ν-process, it is found that when the average shock wave velocity υ sh = 5000 km s −1 and the initial radius r 0 = 8600 km, the maximum abundance ratio of 74 Se and 74 Ge was (10.9 ± 2.2) × 10 −4 from experimental B(GT) values with neutrino temperatures of 2.8 MeV.…”

Neutrinos and Heavy Element Nucleosynthesis

“…The neutrino interactions include charged-(CC) and neutral-current (NC) reactions. Although the neutrino interactions with nuclei are usually negligible, the ν process can contribute entirely or to a significant portion of the production of a handful of rare isotopes including 7 Li, 11 B, 15 N, 19 F, 92 Nb, 98 Tc, 138 La and 180 Ta, as well as two radioisotopes 22 Na and 26 Al (Woosley et al 1990;Heger et al 2005;Byelikov et al 2007;Yoshida et al 2004Yoshida et al , 2005Yoshida et al , 2006aByelikov et al 2007;Yoshida et al 2008;Hayakawa et al 2008Hayakawa et al , 2010Nakamura et al 2010;Austin et al 2011;Cheoun et al 2012;Suzuki and Kajino 2013;Rauscher et al 2013;Hayakawa et al 2013;Lahkar et al 2017;Sieverding et al 2018;Hayakawa et al 2018;Olive and Vangioni 2019;Malatji et al 2019;Kusakabe et al 2019;Li and Li 2022;.…”