Astronomy and Astrophysics – Astrophysics – Galaxy Astrophysics
Scientific paper
2011-06-24
Astronomy and Astrophysics
Astrophysics
Galaxy Astrophysics
accepted for publication in MNRAS, 20 pages, 10 figures, 2 tables
Scientific paper
A new method is presented to describe the evolution of the orbital-parameter distributions for an initially universal binary population in star clusters by means of the currently largest existing library of N-body models. It is demonstrated that a stellar-dynamical operator exists, which uniquely transforms an initial orbital parameter distribution function for binaries into a new distribution depending on the initial cluster mass and half-mass radius, after some time of dynamical evolution. For the initial distribution the distribution functions derived by Kroupa (1995a,b) are used, which are consistent with constraints for pre-main sequence and Class I binary populations. Binaries with a lower energy and a higher reduced-mass are dissolved preferentially. The stellar-dynamical operator can be used to efficiently calculate and predict binary properties in clusters and whole galaxies without the need for further N-body computations. For the present set of N-body models it is found that the binary populations change their properties on a crossing time-scale such that the stellar dynamical operator can be well parametrized as a function of the initial cluster density. Furthermore it is shown that the binary-fraction in clusters with similar initial velocity dispersions follows the same evolutionary tracks as a function of the passed number of relaxation-times. Present-day observed binary populations in star clusters put constraints on their initial stellar densities which are found to be in the range 10^2 - 2x10^5 M_sun pc^-3 for open clusters and a few x 10^3 - 10^8 M_sun pc^-3 for globular clusters, respectively.
Kroupa Pavel
Marks Michael
Oh Seungkyung
No associations
LandOfFree
An analytical description of the evolution of binary orbital-parameter distributions in N-body computations of star clusters does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with An analytical description of the evolution of binary orbital-parameter distributions in N-body computations of star clusters, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and An analytical description of the evolution of binary orbital-parameter distributions in N-body computations of star clusters will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-144309