Chromospheric activity in bright contact binary stars T. Mitnyan, T. Szalai, A. Bódi, L. Kriskovics, K. Vida, B. Cseh, O. Hanyecz, A. Ordasi, A. Pál and J. Vinkó A&A, 635 (2020) A89 Published online: 17 March 2020 DOI: 10.1051/0004-6361/201937214