NUCLEAR-STRUCTURE OF LU-176 AND ITS ASTROPHYSICAL CONSEQUENCES .2. LU-176, A THERMOMETER FOR STELLAR HELIUM BURNING

On the basis of the improved level scheme of Lu-176 it is demonstrated that the stellar s-process production as well as the stellar beta decay rate of that nucleus depend strongly on temperature. This behavior results from the completely different half-lives of the ground state and the isomer; since these states are coupled by induced transitions in the hot stellar photon bath, the effective half-life of Lu-176 is drastically reduced. The 5- state at 838.64 keV was identified as the most efficient mediating level. Consequently, Lu-176 can no longer be considered as a chronometer for the age of the s process; instead, it can be interpreted as an s-process thermometer yielding a temperature range between 2.4 x 10(8) to 3.6 x 10(8) K.