Strong Hα emission in the young planetary mass companion 2MASS J0249−0557 c P. Chinchilla, V. J. S. Béjar, N. Lodieu, M. R. Zapatero Osorio and B. Gauza A&A, 645 (2021) A17 Published online: 22 December 2020 DOI: 10.1051/0004-6361/202038731