Program: GN-2017B-Q-86

We propose to observe Ew Lac in the J, H, K and L bands using GNIRS in cross dispersed mode and in longslit mode, as part of a monitoring campaing of variable Be objects. We intend to follow up the line profile variability of H recombination lines of Br, Pf and Hu series and derive physical properties of the line-forming regions in order to get an insight on the origin and evolution of the envelopes as well as to set constraints to different envelope models and disk forming mechanisms.