Numerical simulations of binary star formation

Hubber, David Anthony. 2006. Numerical simulations of binary star formation. PhD Thesis, Cardiff University.

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Abstract

Binary star formation is the dominant mode of star formation, in contrast to the traditional picture of single star formation. The work in this thesis investigates the properties of binary stars with the aid of numerical simulations, using N-body and Smoothed Particle Hydrodynamics codes. First, we develop a simple model of isolated binary star formation assuming prestellar cores fragment due to rotational instabilities into a ring of N (< 6) stars. We follow the decay of this small-N cluster into singles and multiple systems using the N-body code NBODY3. We can reproduce most of the observed stellar and binary properties of young stars, including the high multiplicity and wide separation distribution, in low-mass star forming regions like Taurus. We extend this further into a model of clustered binary star formation assuming 100 small-N clusters form in fractal clusters of radius 1 pc, similar to many young embedded clusters. We follow the dynamical interactions of these clusters using the N-body code NBODY6. We find that disruptive binary-binary encounters in dense clusters can explain the differences between binary properties in low-density and high-density star forming regions. We develop a new test of Smoothed Particle Hydrodynamics (SPH) called the Jeans Test. We demonstrate that SPH correctly models fragmentation and that under-resolved SPH simulations supress real fragmentation rather than promote artificial fragmentation. Thus binary and multiple systems produced in SPH simulations are real and not the result of numerical effects. Finally, we perform simulations of turbulent prestellar cores in the context of binary star formation. We extend the work of Goodwin, Whitworth & Ward-Thompson (2004) by investigating 2.17 M0 and 4.34 M0 cores.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Physics and Astronomy
Subjects:	Q Science > QC Physics
ISBN:	9781303205286
Date of First Compliant Deposit:	30 March 2016
Last Modified:	10 Jan 2018 03:45
URI:	https://orca.cardiff.ac.uk/id/eprint/56092

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