Abstract Details

Name: Kaustubh Roy
Affiliation: Indian Institute of Science
Conference ID: ASI2021_412
Title : High Mass-ratio Binary Population of Open Clusters and their radial segregation
Authors and Co-Authors : Vikrant V. Jadhav (Indian Institute of Astrophysics, Bangalore), Kaustubh Roy (Indian Institute of Science, Bangalore), Naman Joshi (Indian Institute of Science Education and Research, Bhopal), Annapurni Subramaniam (Indian Institute of Astrophysics, Bangalore)
Abstract Type : Poster
Abstract Category : Stars, ISM and Galaxy
Abstract : Binary stars in open star clusters are important to study dynamical evolution and binary evolution. Binary stars lead to many exotic stellar systems and open cluster provide a testbed to study such systems and binary fraction. Binary fraction through spectroscopy is laborious. The Gaia DR2 colour-magnitude diagrams of cluster members can be used to easily identify high mass-ratio binaries and their dynamical impact through radial distribution. For this study, photometric data of 23 open clusters were obtained from Gaia DR2. We constructed the colour-magnitude diagrams of these clusters and fitted them with PARSEC isochrones. The unresolved binaries were isolated from the distinct second sequence above the main sequence (q>0.75). We plotted radial profiles for each cluster to observe how the radial binary segregation changes with cluster age and metallicity. We also divided the stars in each cluster into magnitude bins to observe how the binary segregation changes with the mass of the stellar population. We define a new parameter ($B^+$) to quantitatively measure radial segregation of binaries with respect to the reference single-star population. In general, we observe that massive binaries are more segregated compared to less massive binaries. Many small and young clusters show no binary segregation; while the oldest clusters show significant binary segregation.