WUNA Lunch Talk:

Ugo Hincelin

University of Virginia, Department of Chemistry

Early phases of Solar System formation: 3D physical & chemical modeling of the collapse of a prestellar dense core.

February 27

12:10PM, Room 230, NRAO, Edgemont Road


Low mass stars, like our Sun, are born from the collapse of a molecular cloud. The matter falls in the center of the cloud, creating a protoplanetary disk surrounding a protostar. Planets and other Solar System bodies will be formed in the disk. The chemical composition of the interstellar matter and its evolution during the formation of the disk are important to better understand the formation process of these planets and other bodies. In order to study the chemical evolution during the early phases of Solar System formation, one needs to know the evolution of the density and the temperature of the matter during the collapse process. Indeed, the chemical composition and its evolution depend mostly on these quantities. We present a tri-dimensional physical and chemical model of the collapse of a prestellar dense core up to the first Larson core formation [1,2]. We have interfaced the state-of- the-art radiation magneto-hydrodynamic (RMHD) model of star formation RAMSES [3,4,5] with the full gas-grain chemical model NAUTILUS [6,7]. NAUTILUS computes the chemical evolution of gas and ices using the time dependent physical structure derived by RAMSES. Within the structure of the object, we identify the different components: the central core, the outflow, the rotating disk, the pseudodisk and the envelope [8]. Our results show that the chemical composition of interstellar matter computed in the initial cloud does not evolve much during the formation of the first Larson core. However, the ice/gas ratio of a given chemical species depends to the considered component, which can be explained by the temperature and density conditions of the component. Besides, we observe some differences in chemical abundances, particularly in the outflow, between cores that have different intensity of magnetic field strength.