title: The formation of massive star systems by accretion.
abstract: Massive stars produce so much light that the radiation pressure they exert on the gas and dust around them is stronger than their gravitational attraction, a condition that has long been expected to prevent them from growing by accretion. We present three-dimensional radiation-hydrodynamic simulations of the collapse of a massive prestellar core and find that radiation pressure does not halt accretion. Instead, gravitational and Rayleigh-Taylor instabilities channel gas onto the star system through nonaxisymmetric disks and filaments that self-shield against radiation while allowing radiation to escape through optically thin bubbles. Gravitational instabilities cause the disk to fragment and form a massive companion to the primary star. Radiation pressure does not limit stellar masses, but the instabilities that allow accretion to continue lead to small multiple systems.
authors.affiliation: Department of Astronomy, University of California, Santa Cruz, CA95064, USA. krumholz@ucolick.org
authors.forename: Mark R
authors.initials: MR
authors.lastname: Krumholz
authors.forename: Richard I
authors.initials: RI
authors.lastname: Klein
authors.forename: Christopher F
authors.initials: CF
authors.lastname: McKee
authors.forename: Stella S R
authors.initials: SS
authors.lastname: Offner
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Cunningham