2007/06/30 by Shinya Wanajo · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Neutrino Physics Research #Scientific Research and Discoveries #astro-ph
paper · pdf · doi:10.1086/521724
5 pages, 3 figures, accepted for publication in ApJL
arxiv created 2007/07/21 · openalex publication_date 2007/08/22 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
The r -process in a low-temperature environment is explored, in which the neutron emission by photodisintegration does not play a role (cold r -process). A semianalytic neutrino-driven wind model is utilized for this purpose. The temperature in a supersonically expanding outflow can quickly drop to a few 10 8 K, where the ( n ,γ)-(γ, n ) equilibrium is never achieved during the heavy r -nuclei synthesis. In addition, the neutron capture competes with the β-decay owing to the low matter density. Despite such nonstandard physical conditions for the cold r -process, a solar-like r -process abundance curve can be reproduced. The cold r -process predicts, however, low lead production compared to that expected in the traditional r -process conditions, which can be a possible explanation for the low lead abundances found in a couple of r -process-rich Galactic halo stars.