The Turbulent Origin of Outflow and Spin Misalignment in Multiple Star Systems

Published in ApJ, 2016

Recommended citation: Offner, S. S. R., Dunham, M. M., Lee, K. I., Arce, H. G., Fielding, D. (2016). "The Turbulent Origin of Outflow and Spin Misalignment in Multiple Star Systems." . ApJ, 827:L11. http://dfielding14.github.io/files/Offner16_outflows.pdf

The protostellar outflows of wide-separation forming binaries frequently appear misaligned. We use magneto-hydrodynamic simulations to investigate the alignment of protostellar spin and molecular outflows for forming binary pairs. We show that the protostellar pairs, which form from turbulent fragmentation within a single parent core, have randomly oriented angular momentum. Although the pairs migrate to closer separations, their spins remain partially misaligned. We produce 12CO(2-1) synthetic observations of the simulations and characterize the outflow orientation in the emission maps. The CO-identified outflows exhibit a similar random distribution and are also statistically consistent with the observed distribution of molecular outflows. We conclude that the observed misalignment provides a clear signature of binary formation via turbulent fragmentation. The persistence of misaligned outflows and stellar spins following dynamical evolution may provide a signature of binary origins for more evolved multiple star systems.

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Stella S. R. Offner, Michael M. Dunham, Katherine I. Lee, Hector G. Arce, Drummond Fielding. The Turbulent Origin of Outflow and Spin Misalignment in Multiple Star Systems. ApJ, 827:L11, Aug 2016