AstroSat/UVIT Study of NGC 663: First detection of Be+sdOB systems in a young star cluster Sneha Nedhath, Sharmila Rani, Annapurni Subramaniam and Elena Pancino A&A, 699 (2025) L1 Published online: 25 June 2025 DOI: 10.1051/0004-6361/202555495