Speaker
Description
Taka Kajino(1-3) and Zhenyu He(1,3)
1 Beihang University, 2 National Astronomical Observatory of Japan, 3 University of Tokyo
The slow and intermediate neutron-capture processes, s- and i-processes, are believed to occur only in asymptotic giant branch stars to provide half of heavy atomic nuclei 90 ≤ A in the Milky Way. We found, for the first time, that the collapsar which is an explosion of single massive star collapsing to a black hole is an astrophysical site for s- and i-processes [1] as well as rapid neutron capture process, r-process [2]. We show significant roles of several neutron-capture reactions on unstable nuclei near the stability line for the i-process as well as those on extremely neutron-rich nuclei for the r-process. We propose that the pronounced odd-even effect in the mass abundance pattern near rare earth elements in metal-deficient halo stars could be a piece of observational evidence [1,3].
[1] Z. He, M. Kusakabe, T. Kajino, S.-G. Zhou, H. Koura, & S. Chiba, submitted (2022).
[2] Y. Yamazaki, Z. He, T. Kajino, G. J. Mathews, M. A. Famiano, X.-D. Tang, J.-R. Shi, ApJ. 933 (2022), 112.
[3] Z. He, M. Kusakabe, T. Kajino, S.-G. Zhou, H. Koura, & S. Chiba, in preparation (2022).
