Distinguishing between different mechanisms of FU-Orionis-type luminosity outbursts Eduard I. Vorobyov, Vardan G. Elbakyan, Hauyu Baobab Liu and Michihiro Takami A&A, 647 (2021) A44 Published online: 04 March 2021 DOI: 10.1051/0004-6361/202039391