Eur. Phys. J. A (2006) 27: 75-78
https://doi.org/10.1140/epja/i2006-08-010-1

Nuclear Physics in Astrophysics II

Relation between the ¹⁶O(α,γ)²⁰Ne reaction and its reverse ²⁰Ne(γ,α)¹⁶O reaction in stars and in the laboratory

¹ Diakoniekrankenhaus, D-74523, Schwäbisch Hall, Germany
² Centre de Recherches du Cyclotron, UCL, Louvain-la-Neuve, Belgium
³ PNTPM, Université Libre de Bruxelles, Brussels, Belgium
⁴ Konan University, Kobe, Japan

^* e-mail: hiro@konan-u.ac.jp

Received: 24 May 2005
Accepted: 20 December 2005
Published online: 23 February 2006

Abstract

The astrophysical reaction rates of the ¹⁶O (α,γ) ²⁰Ne capture reaction and its inverse ²⁰Ne (γ,α) ¹⁶O photodisintegration reaction are given by the sum of several narrow resonances and a small direct capture contribution at low temperatures. Although the thermal population of low-lying excited states in ¹⁶O and ²⁰Ne is extremely small, the first excited state in ²⁰Ne plays a non-negligible role for the photodisintegration rate. Consequences for experiments with so-called quasi-thermal photon energy distributions are discussed.