Chemical Variation among Protostellar Cores: Dependence on Prestellar
  Core Conditions
  Hot corino chemistry and warm carbon chain chemistry (WCCC) are driven by
gas-grain interactions in star-forming cores: radical-radical recombination
reactions to form complex organic molecules (COMs) in the ice mantle,
sublimation of CH$_4$ and COMs, and their subsequent gas-phase reactions. These
chemical features are expected to depend on the composition of ice mantle which
is set in the prestellar phase. We calculated the gas-grain chemical reaction
network considering a layered ice-mantle structure in star-forming cores, to
investigate how the hot corino chemistry and WCCC depend on the physical
condition of the static phase before the onset of gravitational collapse. We
found that WCCC becomes more active, if the temperature is lower, or the visual
extinction is lower in the static phase, or the static phase is longer.
Dependence of hot corino chemistry on the static-phase condition is more
complex. While CH$_3$OH is less abundant in the models with warmer static
phase, some COMs are formed efficiently in those warm models, since there are
various formation paths of COMs. If the visual extinction is lower, photolysis
makes COMs less abundant in the static phase. Once the collapse starts and
visual extinction increases, however, COMs can be formed efficiently. Duration
of the static phase does not largely affect COM abundances. Chemical diversity
between prototypical hot corinos and hybrid sources, in which both COMs and
carbon chains are reasonably abundant, can be explained by the variation of
prestellar conditions. Deficiency of gaseous COMs in prototypical WCCC sources
is, however, hard to reproduce within our models.
