2 research outputs found
Binary Star Evolution in Different Environments: Filamentary, Fractal, Halo and Tidal-tail Clusters
Using membership of 85 open clusters from previous studies (Pang et al.
2021a,b, 2022b; Li et al. 2021) based on Gaia DR3 data, we identify binary
candidates in the color-magnitude diagram, for systems with mass ratio q > 0.4.
The binary fraction is corrected for incompleteness at different distances due
to the Gaia angular resolution limit. We find a decreasing binary fraction with
increasing cluster age, with substantial scatter. For clusters with a total
mass > 200, the binary fraction is independent of cluster mass. The
binary fraction depends strongly on stellar density. Among four types of
cluster environments, the lowest-density filamentary and fractal stellar groups
have the highest mean binary fraction: 23.6% and 23.2%, respectively. The mean
binary fraction in tidal-tail clusters is 20.8%, and is lowest in the densest
halo-type clusters: 14.8%. We find clear evidence of early disruptions of
binary stars in the cluster sample. The radial binary fraction depends strongly
on the cluster-centric distance across all four types of environments, with the
smallest binary fraction within the half-mass radius , and increasing
towards a few . Only hints of mass segregation is found in the target
clusters. The observed amount of mass segregation is not significant to
generate a global effect inside the target clusters. We evaluate the bias of
unresolved binary systems (assuming a primary mass of 1) in 1D
tangential velocity, which is 0.1-1. Further studies are
required to characterize the internal star cluster kinematics using Gaia proper
motions