  Abundances for C18O, CS, NH3, H2CO, C3H2, and N2H+ and upper limits for the
abundances of 13CO and HCO+ are derived for gas within the Bok globule B68
using our own BIMA array data, single-dish data from the literature, and Monte
Carlo radiative transfer models. B68 has had its density structure well
determined, removing a major uncertainty from abundance determinations. All
abundances for B68 are lower than those derived for translucent and cold dense
clouds, but perhaps only significantly for N2H+, NH3, and C3H2. CS depletion
toward the extinction peak of B68 is hinted at by the large offset between the
extinction peak and the position of maximum CS line brightness. C18O and N2H+
abundances derived here are consistent with recently determined values at
positions observed in common.

Astrophysics