Revolutionizing our View of Disk and Multiple Star Formation: New Frontiers Explored by ALMA and the VLA

Protostellar disks are thought to form early in the star-formation process due to conservation of angular momentum. These disks are the future sites of planet formation, but may also be the sites of binary/multiple star formation if the disk is massive enough to be gravitationally unstable. There is now growing evidence that a substantial amount of disk evolution takes place during the protostellar phase and that these embedded, protostellar disks may be the true initial conditions of planet formation. Using ALMA and the VLA, we are conducting large continuum surveys (with a few molecular lines) of protostars in the nearby Perseus and Orion star-forming regions (with 15-40 AU resolution) to characterize the size, masses, and physical density structure of disks throughout the protostellar phase. The multi-wavelength data enable us to assess their planet-forming potential in terms of disk mass, grain growth, and radial distribution of grain sizes. At the same time, we are using these survey data to conduct the broadest characterization of protostellar multiplicity to date.