Recent Advances in the Collapse and Fragmentation of Turbulent Molecular Cloud Cores

Observations of stars in the vicinity of the Sun show that binary systems are prevalent and appear to be a general outcome of the star-formation process. One of the major goals of this research is to understand the nature of the formation of binary and multiple stellar systems with typical low-mass stars (∼ 0.2 to 3 M ) and the physical properties of these systems. Basic questions concerning this process remain unanswered. What determines the fraction of an unstable cloud that will fragment into protostellar objects? What determines the pattern of stellar clustering into binaries and multiple systems? Even after fragmentation occurs, we have little understanding of the subsequent collapse. Consequently, it is unclear how the mass distribution of fragments maps onto eventual stellar masses, something we must understand to explain the stellar initial mass function. We will first discuss the development of the numerical methodology that will contribute to answering these questions. This technology consists of a 3-D parallel, adaptive mesh refinement (AMR) self-gravitational, radiation-hydrodynamics code that we have developed. We will present new results for the gravitational collapse and fragmentation of marginally stable turbulent molecular cloud cores and follow the collapse of high-mass fragments as they interact with the radiation of the protostars forming at their centers. We will discuss the theoretical difficulties in forming binary stars and the role of turbulence in their formation.