EPoS Contribution
EPoS Contribution
Toward truly initial conditions for chemistry in starless cores

Dmitry Wiebe
Institute of Astronomy of the RAS, Moscow, Russia
When people refer to the initial conditions for star formation, they often apprehended them as a stage in which the molecular cloud has already fragmented into more or less distinct starless (prestellar) cores. However, this stage can only be seen as initial from the point of view of the terminal prestellar collapse. At the same time, it is by no means initial from the chemical point of view. Available observations of chemistry in diffuse interstellar clouds show that their molecular composition is surprisingly rich, so that the chemical evolution in prestellar cores hardly starts from purely atomic abundances. This may have sizeable consequences for the interpretation of future observations with high angular resolution and/or sensitivity. We developed a chemo-dynamical model for a pre-starless stage of a prestellar core evolution, with a special emphasis on gas and dust thermal balance, photoreactions, including H2 photodissociation, and surface chemistry, including stochastic treatment of H2 formation. We study how different scenarios of a starless core formation are reflected in its "initial" chemical composition. Effects of the environment are also illustrated.