Ambrose, Hannah E. and Whitworth, A. P.  ORCID: https://orcid.org/0000-0002-1178-5486
2024.
The formation of multiples in small-<i>N</i> subclusters.
Monthly Notices of the Royal Astronomical Society
10.1093/mnras/stae2556
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Abstract
We explore the relative percentages of binary systems and higher-order multiples that are formed by pure stellar dynamics, within a small subcluster of N stars. The subcluster is intended to represent the fragmentation products of a single isolated core, after most of the residual gas of the natal core has dispersed. Initially the stars have random positions, and masses drawn from a log-normal distribution. For low-mass cores spawning multiple systems with Sun-like primaries, the best fit to the observed percentages of singles, binaries, triples and higher-order systems is obtained if a typical core spawns on average between N = 4.3 and 5.2 stars, specifically a distribution of N with mean $\mu _{_{N}}\sim 4.8$ and standard deviation $\sigma _{_N}\sim 2.4$. This fit is obtained when $\sim 50\%$ of the subcluster’s internal kinetic energy is invested in ordered rotation and $\sim 50\%$ in isotropic Maxwellian velocities. There is little dependence on other factors, for example mass segregation or the rotation law. Whilst such high values of N are at variance with the lower values often quoted (i.e. N = 1 or 2), very similar values (N = 4.3 ± 0.4 and N = 4.5 ± 1.9) have been derived previously by completely independent routes, and seem inescapable when the observed distribution of multiplicities is taken into account.
| Item Type: | Article |
|---|---|
| Date Type: | Published Online |
| Status: | Published |
| Schools: | Physics and Astronomy |
| Additional Information: | License information from Publisher: LICENSE 1: URL: https://creativecommons.org/licenses/by/4.0/, Start Date: 2024-11-14 |
| Publisher: | Oxford University Press |
| ISSN: | 0035-8711 |
| Funders: | STFC |
| Date of First Compliant Deposit: | 25 November 2024 |
| Last Modified: | 04 Dec 2024 12:38 |
| URI: | https://orca.cardiff.ac.uk/id/eprint/174274 |
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