Physical properties of bright Ca II K fibrils in the solar chromosphere Sepideh Kianfar, Jorrit Leenaarts, Sanja Danilovic, Jaime de la Cruz Rodríguez and Carlos José Díaz Baso A&A, 637 (2020) A1 Published online: 30 April 2020 DOI: 10.1051/0004-6361/202037572