• DOI:10.1093/mnras/stac207
• Corpus ID: 246210311

UOCS VII. Blue Straggler Populations of Open Cluster NGC 7789 with UVIT/AstroSat

@inproceedings{Vaidya2022UOCSVB,
  title={UOCS VII. Blue Straggler Populations of Open Cluster NGC 7789 with UVIT/AstroSat},
  author={Kaushar Vaidya and Anju Panthi and Manan Agarwal and Sindhu Pandey and Khushboo K. Rao and Vikrant V. Jadhav and Annapurni Subramaniam},
  year={2022}
}

• Kaushar Vaidya, Anju Panthi, +4 authors A. Subramaniam
• Published 21 January 2022
• Physics

NGC 7789 is a ∼1.6 Gyr old, populous open cluster located at ∼2000 pc. We characterize the blue straggler stars (BSS) of this cluster using the Ultraviolet (UV) data from the UVIT/AstroSat. We present spectral energy distributions (SED) of 15 BSS candidates constructed using multi-wavelength data ranging from UV to IR wavelengths. In 8 BSS candidates, a single temperature SED is found to be satisfactory. We discover hot companions in 5 BSS candidates. The hot companions with Teff ∼11750–15500 K, R ∼0.069–0.242 R , and L ∼0.25–1.55 L , are most likely extremely low mass (ELM) white dwarfs (WDs) with masses smaller than ∼0.18 M , and thereby confirmed post mass transfer systems. We discuss the implication of this finding in the context of BSS formation mechanisms. Two additional BSS show excess in one or more UV filters, and may have a hot companion, however we are unable to characterize them. We suggest that at least 5 of the 15 BSS candidates (33%) studied in this cluster have formed via the mass-transfer mechanism.