Gas flow and accretion via spiral streamers and circumstellar disks in a young binary protostar
Gas flows and disks in a young binary Many stars are in binary systems, pairs of stars gravitationally bound to each other, often with the two components having similar masses. It remains unclear how these systems assemble and accrete material. Alves et al. made high-resolution observations of a young binary star that is still in the process of forming. A large disk surrounds both stars, and each component also has its own smaller circumstellar disk. Spiral filaments of dust and gas connect the small disks to the larger one. Material is accreting preferentially onto the star that currently has a lower mass, driving the masses toward similar values. Science, this issue p. 90 A binary protostar system contains spiral streamers of gas and dust that drive the forming stars toward similar masses. The majority of stars are part of gravitationally bound stellar systems, such as binaries. Observations of protobinary systems constrain the conditions that lead to stellar multiplicity and subsequent orbital evolution. We report high–angular resolution observations of the circumbinary disk around [BHB2007] 11, a young binary protostar system. The two protostars are embedded in circumstellar disks that have radii of 2 to 3 astronomical units and probably contain a few Jupiter masses. These systems are surrounded by a complex structure of filaments connecting to the larger circumbinary disk. We also observe accretion and radio jets associated with the protobinary system. The accretion is preferentially onto the lower-mass protostar, consistent with theoretical predictions.