2014MNRAS.441..784P -
Mon. Not. R. Astron. Soc., 441, 784-789 (2014/June-2)
Spatial differences between stars and brown dwarfs: a dynamical origin ?
PARKER R.J. and ANDERSEN M.
Abstract (from CDS):
We use N-body simulations to compare the evolution of spatial distributions of stars and brown dwarfs in young star-forming regions. We use three different diagnostics: the ratio of stars to brown dwarfs as a function of distance from the region's centre, R_SSR, the local surface density of stars compared to brown dwarfs, ΣLDR, and we compare the global spatial distributions using the ΛMSR method. From a suite of 20 initially statistically identical simulations, 6/20 attain R_SSR ≪1 and ΣLDR ≪ 1 and ΛMSR ≪ 1, indicating that dynamical interactions could be responsible for observed differences in the spatial distributions of stars and brown dwarfs in star-forming regions. However, many simulations also display apparently contradictory results - for example, in some cases the brown dwarfs have much lower local densities than stars (ΣLDR ≪ 1), but their global spatial distributions are indistinguishable (ΛMSR = 1) and the relative proportion of stars and brown dwarfs remains constant across the region (R_SSR = 1). Our results suggest that extreme caution should be exercised when interpreting any observed difference in the spatial distribution of stars and brown dwarfs, and that a much larger observational sample of regions/clusters (with complete mass functions) is necessary to investigate whether or not brown dwarfs form through similar mechanisms to stars.
Abstract Copyright:
© 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society (2014)
Journal keyword(s):
methods: numerical - brown dwarfs - stars: formation - stars: kinematics and dynamics - stars: low-mass - open clusters and associations: general
Simbad objects:
6
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