  The astrophysical reaction rates of the 16O(a,g)20Ne capture reaction and its
inverse 20Ne(g,a)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.
