I will present yet another update on a project that I and my
collaborators began in 1978. We're persistent if nothing else.

Helium-3 is one of the isotopes made in the Big Bang. In addition,
standard stellar models predict that helium-3 is made in large
quantities in solar analog stars. Most of this helium-3 should make
its way into the ISM via stellar winds and planetary
nebulae. Planetary nebulae should be enhanced by perhaps a factor of
100 over the cosmological and protosolar nebula values. If
standard stellar models had been correct, we would have finished this
experiment in 1985.

After much angst we have found that the ISM shows very little
enhancement of helium-3 over the cosmological value. On the
other hand, some (actually only 1) planetary nebulae show the large
abundance predicted by standard stellar models. So we have managed to
show that stars produce helium-3 and that stars do not produce
helium-3. We are using new radio telescopes to increase our PN
sample. To see whether these clarify or further muddle the issue you'll
have to come to the talk or ply me with fine Italian wine afterwards.