Chemical and physical characterization of collapsing low-mass prestellar
  dense cores
  The first hydrostatic core, also called the first Larson core, is one of the
first steps in low-mass star formation, as predicted by theory. With recent and
future high performance telescopes, details of these first phases become
accessible, and observations may confirm theory and even bring new challenges
for theoreticians. In this context, we study from a theoretical point of view
the chemical and physical evolution of the collapse of prestellar cores until
the formation of the first Larson core, in order to better characterize this
early phase in the star formation process. We couple a state-of-the-art
hydrodynamical model with full gas-grain chemistry, using different assumptions
on the magnetic field strength and orientation. We extract the different
components of each collapsing core (i.e., the central core, the outflow, the
disk, the pseudodisk, and the envelope) to highlight their specific physical
and chemical characteristics. Each component often presents a specific physical
history, as well as a specific chemical evolution. From some species, the
components can clearly be differentiated. The different core models can also be
chemically differentiated. Our simulation suggests some chemical species as
tracers of the different components of a collapsing prestellar dense core, and
as tracers of the magnetic field characteristics of the core. From this result,
we pinpoint promising key chemical species to be observed.
