WHAT IS THE PROBLEM WITH HE-3

We consider the galactic evolutionary history of He-3 in models which deplete deuterium by as much as a factor of 2 to similar to 15 from it s primordial value to its present-day observed value in the interstell ar medium (ISM). We show that when 3He production in low-mass stars (1 -3 M(.)) is included over the history of the galaxy, He-3 is greatly o verproduced and exceeds the inferred solar values and the abundances d etermined in galactic H II regions. Furthermore, the ISM abundances sh ow a disturbing dispersion which is difficult to understand from the p oint of view of standard chemical evolution models. In principle, reso lution of the problem may lie in either (1) the calculated He-3 produc tion in low-mass stars; (2) the observations of the He-3 abundance; or (3) an observational bias toward regions of depleted He-3. Since He-3 observations in planetary nebula support the calculated He-3 producti on in low-mass stars, option (1) is unlikely. We will argue for option (3) since the He-3 interstellar observations are indeed made in regio ns dominated by massive stars in which He-3 is destroyed. In conclusio n, we note that the problem with He-3 seems to be galactic and not cos mological.