Revealing the dust grain size in the inner envelope of the Class I protostar Per-emb-50 C. Agurto-Gangas, J. E. Pineda, L. Szűcs, L. Testi, M. Tazzari, A. Miotello, P. Caselli, M. Dunham, I. W. Stephens and T. L. Bourke A&A, 623 (2019) A147 Published online: 25 March 2019 DOI: 10.1051/0004-6361/201833666