Spectroscopic variability of massive pre-main-sequence stars in M17 A. R. Derkink, M. C. Ramírez-Tannus, L. Kaper, A. de Koter, F. Backs, J. Poorta and M. L. van Gelder A&A, 681 (2024) A112 Published online: 25 January 2024 DOI: 10.1051/0004-6361/202347369