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

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. [ABSTRACT FROM AUTHOR]