Numerical simulations of protostellar encounters — II. Coplanar disc–disc encounters |
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Authors: | S. J. Watkins,A. S. Bhattal,H. M. J. Boffin,N. Francis,& A. P. Whitworth |
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Affiliation: | Department of Physics and Astronomy, University of Wales, Cardiff CF2 3YB |
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Abstract: | It is expected that an average protostar will undergo at least one impulsive interaction with a neighbouring protostar whilst a large fraction of its mass is still in a massive, extended disc. Such interactions must have a significant impact upon the evolution of the protostars and their discs. We have carried out a series of simulations of coplanar encounters between two stars, each possessing a massive circumstellar disc, using an SPH code that models gravitational, hydrodynamic and viscous forces. We find that during a coplanar encounter, disc material is swept up into a shock layer between the two interacting stars, and the layer then fragments to produce new protostellar condensations. The truncated remains of the discs may subsequently fragment; and the outer regions of the discs may be thrown off to form circumbinary disc-like structures around the stars. Thus coplanar disc–disc encounters lead efficiently to the formation of multiple star systems and small- N clusters, including substellar objects. |
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Keywords: | accretion, accretion discs hydrodynamics instabilities methods: numerical binaries: general stars: formation |
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