GlobULeS. IV. UVIT/AstroSat Detection of Extremely Low Mass White Dwarf Companions to Blue Straggler Stars in NGC 362

We report the discovery of extremely low-mass white dwarfs (ELM WDs) as a companion blue straggler stars (BSSs) in Galactic globular cluster NGC 362 using images from AstroSats Ultra Violet Imaging Telescope (UVIT). Spectral Energy Distributions (SEDs) for 26 FUV bright member BSSs are created data UVIT, UVOT, Gaia EDR3, and 2.2 m ESO/MPI telescope. A single SED is fitted to 14 BSSs, whereas double-SED fits revealed ELM WDs binary companions 12 studied. The effective temperature, radius, luminosity mass found have range (Teff = 9750-18000 K, R 0.1-0.4 Rsun, L 0.4-3.3 Lsun, M =0.16-0.20 Msun). These suggest that post-mass-transfer systems formed through Case A/B transfer pathway. To best our knowledge, this first finding BSS clusters. This known sequence (as classified by SEDs) follow collisional colour-magnitude diagram. cooling ages 9 be younger than 500 Myr. Though may during core-collapse (approx 200 Myr) or part dynamical evolution cluster, they provide new insights on dynamics cluster.