Name: Kaushar Vaidya
Affiliation: Birla Institute of Technology and Science Pilani
Conference ID : ASI2022_701
Title : Blue Straggler Populations of Open Cluster NGC 7789 with UVIT/AstroSat
Authors : Kaushar Vaidya, Anju Panthi, Manan Agarwal, Sindhu Pandey, Khushboo K. Rao, Vikrant Jadhav, & Annapurni Subramaniam
Abstract Type: Oral
Abstract Category : Stars, ISM and Galaxy
Abstract : 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 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. We discover hot companions in 5 BSS candidates. The hot companions are most likely extremely low mass (ELM) white dwarfs (WDs) with masses smaller than 0.20 solar mass. Two additional BSS show excess in one or more UV filters, and may have a hot companion, however, we are unable to characterize them. In 8 BSS candidates, a single temperature SED is found to be satisfactory. Based on our analysis, we suggest that at least 5 of the 15 BSS candidates studied in this cluster have formed via the mass-transfer mechanism.