BiPoS1 – a computer programme for the dynamical processing of the initial binary star population. Issue 1 (12th November 2021)

• Record Type: Journal Article
• Authors: Dabringhausen, J; Marks, M; Kroupa, P
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 510:Issue 1(2022)
• Page Start: 413
• Page End: 432
• Publication Date: 2021-11-12
• Subjects: methods: numerical -- software: public release -- binaries: general -- stars: kinematics and dynamics -- stars: pre-main-sequence -- stars: statistics; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stab3288
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: The first version of the Binary Population Synthesizer (BiPoS1 ) is made publicly available. It allows to efficiently calculate binary distribution functions after the dynamical processing of a realistic population of binary stars during the first few Myr in the hosting embedded star cluster. Instead of time-consuming N -body simulations, BiPoS1 uses the stellar dynamical operator $\Omega _{\rm dyn}^{\rho _{\rm ecl}}(\log _{10}(E_{\rm b}), t)$, which determines the fraction of surviving binaries depending on the binding energy of the binaries, E b . The Ω-operator depends on the initial star cluster density, ρecl, as well as the time, t, until the residual gas of the star cluster is expelled. BiPoS1 has also a galactic-field mode, in order to synthesize the stellar population of a whole galaxy. At the time of gas expulsion, the dynamical processing of the binary population is assumed to efficiently end due to the subsequent expansion of the star cluster. While BiPoS1 has been used previously unpublished, here we demonstrate its use in the modelling of the binary populations in the Orion Nebula Cluster, in OB associations and as an input for simulations of globular clusters.