On the Binary Properties and the Spatial and Kinematical Distribution of Young Stars

Abstract

The effects which star cluster concentration and binarity have on observable parameters, that characterise the dynamical state of a population of stars after their birth aggregate dissolves, are investigated. To this end, the correlations between ejection velocity, binary proportion, mean system mass, binary orbital period and mass ratio are quantified for simulated aggregates. These consist of a few hundred low-mass binary and single stars, and have half-mass radii in the range 2.5 to 0.08 pc. The primordial binary-star population has a period distribution similar to that observed in Taurus-Auriga for pre-main sequence binaries. The findings presented here are useful for interpreting correlations between relative locations and proper motions, binary properties and masses of young stellar systems within and surrounding star forming regions, and of stellar systems escaping from Galactic clusters. (shortened)