Bound state beta-decay and ifs astrophysical relevance

Bound state beta-decay of fully ionized Dy-163 and Re-187 nuclei, circulating in a storage cooler ring has been observed from the growth of their hydrogenlike daughter nuclei using two methods. As neutral atom,Dy-163 is stable, and Re decays with T-1/2 43Gyr. The half lifes of Dy-163(66+) and Re-187(75+) determined by bound state beta-decays to their respective K-orbits have been determined to T-1/2 = (48 +/- 3) d and T-1/2 = 32.9 +/- 2.0 yr, respectively. The astrophysical relevance of both observations will be presented. The observed bound state beta-decay of Dy-163(66+) explains the high abundance of Er-164, due to a s-process sequence including bound state beta-decay of D-163(66+). From the observation of the bound state beta-decay of Re-187(75) the Re-187-Os-187- cosmochronometer may be calibrated using chemical star evolution models, and including reastration effects. From recent abundance measurements of Re- and Os-isotopes in meteorites the age of the Galaxy was deduced as (15+/-2)Gyr, with our new calibration.