  Forming stars emit a significant amount of radiation into their natal
environment. While the importance of radiation feedback from high-mass stars is
widely accepted, radiation has generally been ignored in simulations of
low-mass star formation. I use ORION, an adaptive mesh refinement (AMR)
three-dimensional gravito-radiation-hydrodynamics code, to model low-mass star
formation in a turbulent molecular cloud. I demonstrate that including
radiation feedback has a profound effect on fragmentation and protostellar
multiplicity. Although heating is mainly confined within the core envelope, it
is sufficient to suppress disk fragmentation that would otherwise result in
low-mass companions or brown dwarfs. As a consequence, turbulent fragmentation,
not disk fragmentation, is likely the origin of low-mass binaries.

Solar and Stellar Astrophysics