Lithium abundances in AGB stars and a new estimate for the 7Be life-time

6th Nuclear Physics in Astrophysics

物理学;天文学

Palmerini, S.^1 ; Busso, M.^2,6 ; Simonucci, S.^3,6 ; Taioli, S.^4,5,6

Departamento de Fisica Teórica y Del Cosmos, Universidad de Granada, Spain^1

Dipartimento di Fisica, Università Degli Studi di Perugia, Italy^2

Dipartimento di Fisica, Università Degli Studi di Camerino, Italy^3

Interdisciplinary Lab for Computational Science, FBK/CMM, Trento, Italy^4

Dipartimento di Chimica, Università Degli Studi di Bologna, Bologna, Italy^5

INFN Sezione di Perugia, Italy^6

关键词: Affect modeling;    Combined operations;    Electron capture;    Half lives;    Life-times;    Mixing process;    Orders of magnitude;    Wide spreads;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/665/1/012014/pdf
DOI  :  10.1088/1742-6596/665/1/012014

学科分类：天文学(综合)

来源: IOP

【 摘 要 】

In most cases RGB and AGB stars with M ≤ 2Modestroy Li (which is instead synthesized trough electron-captures on7Be). This occurs through the combined operation of mixing processes and proton captures, when H-burning operates close to the envelope. Observed Li abundances are however difficult to explain, as they cover a wide spread. Various uncertainties affect model attempts, but so far the largest one concerns the processes of bound and free e- captures on7Be, hence its life-time, whose known estimates are valid only for solar conditions. RGB and AGB stages have temperatures and densities below the envelope covering a wide range and differing from solar by up to a factor of five for T and up to five orders of magnitudes for ρ, hence extrapolations are unreliable. Recently, we presented an estimate of the7Be half-life based on a fully quantistic method that goes beyond the Debye-Huckel approximation. Here we discuss its consequences on Li nucleosynthesis in low mass AGB stars.