HD 75149 multi-epoch spectra

We modeled the H{alpha} emission, absorption, and P-Cygni profiles using the ISOSCELES grid and the delta-slow hydrodynamic regime. H{alpha} shows variability in intervals of a few days, including P-Cygni changes, while metal lines show small RV amplitudes, consistent with pulsating oscillations. The largest variation in the mass-loss rate corresponds to an increase of a factor of 1.8 within four days.

In contrast, the terminal velocity remains barely affected during the same time interval. The pronounced variation observed in hydrogen lines, in contrast with the variability of other lines, suggests that it is due to mass-loss rate episodes driven by a slow wind occurring on a timescale comparable to photometric variations. We found no evidence of a close binary companion in the sample used, but we cannot completely exclude the possibility of a wide or low-inclination companion.