Lifetime measurements of states inO15

Measurement of lifetimes inMg23

“…The radionuclide 22 Na is thought to be produced in significant amounts in ONe-type classical novae [1]. It decays by β + ν e emission to the first excited state in 22 Ne with a mean lifetime of 3.75 yr.…”

“…It decays by β + ν e emission to the first excited state in 22 Ne with a mean lifetime of 3.75 yr. The daughter nucleus quickly relaxes to the ground state by emitting a γ ray with a characteristic energy of 1275 keV.…”

“…The daughter nucleus quickly relaxes to the ground state by emitting a γ ray with a characteristic energy of 1275 keV. The lifetime of 3.75 yr is sufficiently short to ensure that the ejected 22 Na is still close to the nova by the time the decay occurs, making it possible to correlate the γ -ray intensity with other observational properties, yet sufficiently long for the 22 Na to survive beyond the opaque phase of the explosion, allowing the γ ray to be observed. These fortunate circumstances make 22 Na the most promising candidate for detection of nuclear γ -ray lines from novae [2].…”

“…These fortunate circumstances make 22 Na the most promising candidate for detection of nuclear γ -ray lines from novae [2]. Nova models predict 22 Na γ -ray fluxes 1 order of magnitude below the observational upper limit [3]. While detection does not appear to be imminent, it seems reasonable to assume that it will happen within the foreseeable future [4], and consequently reliable estimates of 22 Na yields in novae are desirable.…”

“…While detection does not appear to be imminent, it seems reasonable to assume that it will happen within the foreseeable future [4], and consequently reliable estimates of 22 Na yields in novae are desirable. Nova production of 22 Na may also be relevant for explaining the nonstandard abundance of 22 Ne observed in Ne-E meteorites [5].…”