We determine the binary star fraction as a function of radius in NGC 1818, a young rich cluster in the Large Magellanic Cloud, using Hubble Space Telescope images in bands F336W (∼U) and F555W (∼V). Our sample includes binaries with A/primary ∼2-5.5 M⊙ and Msecondary ≳ 0.7Mprimary. The binary fraction increases towards the cluster centre, from ∼20 ± 5 per cent in the outer parts, to ∼35 ± 5 per cent inside the core. This increase is consistent with dynamical mass segregation and need not be primordial. We compare our results with expectations from N-body models, and discuss the implications for the formation and early evolution of such clusters.
|Original language||English (US)|
|Number of pages||6|
|Journal||Monthly Notices of the Royal Astronomical Society|
|State||Published - Nov 1 1998|
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science