Binary formation in stellar clusters |
| |
| Authors: | Anthony J Horton Matthew R Bate Ian A Bonnell |
| |
| Institution: | Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA;School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS |
| |
| Abstract: | We consider how the tidal potential of a stellar cluster or a dense molecular cloud affects the fragmentation of gravitationally unstable molecular cloud cores. We find that molecular cloud cores which would collapse to form a single star in the absence of tidal shear, can be forced to fragment if they are subjected to tides. This may enhance the frequency of binaries in star-forming regions such as Ophiuchus and the frequency of binaries with separations ?100 au in the Orion Trapezium Cluster. We also find that clouds which collapse to form binary systems in the absence of a tidal potential will form bound binary systems if exposed to weak tidal shear. However, if the tidal shear is sufficiently strong, even though the cloud still collapses to form two fragments, the fragments are pulled apart while they are forming by the tidal shear and two single stars are formed. This sets an upper limit for the separation of binaries that form near dense molecular clouds or in stellar clusters. |
| |
| Keywords: | hydrodynamics binaries: general stars: formation open clusters and associations: general |
|
|
