The Spitzer c2d Survey of Nearby Dense Cores VII: Chemistry and Dynamics
  in L43
  We present results from the Spitzer Space Telescope and molecular line
observations of 9 species toward the dark cloud L43. The Spitzer images and
molecular line maps suggest it has a starless core and a Class I protostar
evolving in the same environment. CO depletion is seen in both sources, and
DCO+ lines are stronger toward the starless core. With a goal of testing the
chemical characteristics from pre- to protostellar stages, we adopt an
evolutionary chemical model to calculate the molecular abundances and compare
with our observations. Among the different model parameters we tested, the
best-fit model suggests a longer total timescale at the pre-protostellar stage,
but with faster evolution at the later steps with higher densities.
