Galactic Evolution of D and 3He Including Stellar Production of 3He

New stellar models which track the production and destruction of ³He (and D) have been evolved for a range of stellar masses (0. 65\ M/M\\ 100), metallicities (0. 01 \ Z/Z\ \ 1) and initial (main sequence) ³He mass fractions (10^-5 \ X₃, ₌ₒ \ 10^-3). Armed with the ³He yields from these stellar models we have followed the evolution of D and ³He using a variety of chemical evolution models with and without infall of primordial or processed material. Production of new ³He by the lower mass stars overwhelms any reasonable primordial contributions and leads to predicted abundances in the presolar nebula and/or the present interstellar medium in excess of the observationally inferred values. This result, which obtains even for zero primordial D and ³He, and was anticipated by Rood, Steigman \\ it is driven by the large ³He yields from low mass stars. In an attempt to ameliorate this problem we have considered a number of non-standard models in which the yields from low mass stars have been modified. Although several of these non-standard models may be consistent with the ³He data, they may be inconsistent with observations of ^12C/^13C, ^18O and, most seriously, the super-³He rich planetary nebulae (Rood, Bania \\& Wilson 1992). Even using the most extreme of these non-standard models (Hogan 1995), we obtain a generous upper bound to pre-galactic ³He: X₃₏ \ 3. 2 \10^-5 which, nonetheless, leads to a stringent lower bound to the universal density of nucleons.