This award supports the continuation of the detailed study of low-mass (i.e., like the Sun) star formation. Given sufficient mass to overcome the thermal and turbulent pressures in the interstellar medium, a condensing protostellar object forms with a disk surrounding it. That disk spins because of conservation of angular momentum, and some of that angular momentum may be transferred to the young stellar object. Magnetic fields seem to play some role in the transfer. Strong winds also emanate, but whether from the disk or the protostar is not known. Dr. Shu will study the structure and evolution of the winds, magnetic evolution, gravitational instabilities, collapse of an isothermal sphere, and disks around O stars. About 5 billion years ago our Sun, with its attending planets, was formed from an interstellar medium enriched by previous stellar deaths: stars send their remains into the surrounding medium to await the next cycle of local star formation. Understanding the evolution of galaxies requires understanding these cycles. Understanding the evolution of a universe made of galaxies means that we must first understand how stars form in our own Galaxy. This proposed research will take another large step along that path.
