2021MNRAS.507.3285C

The aim of this work was to continue the monitoring of the H₂O maser emission in IRAS 16293-2422 to detect superflares. We have been observing H₂O maser emission at a wavelength of 1.35 cm towards the source IRAS 16293-2422 since 1999. The observations have been carried out with the 22-m radio telescope of the Pushchino Radio Astronomy Observatory (Russia). In 2007-2018, we also conducted several sessions of observations in OH lines at a wavelength of 18 cm in both circular polarizations with the Nancay Radio Telescope (France). Between 1997 and 2021, we observed three cycles of high activity of the H₂O maser with a period of 8 yr. This variability could be related to the changing activity of the protostar in the tight binary system of IRAS 16293-2422 in the process of its formation. This variability could be related to an increase in the activity of the tight binary protostar IRAS 16293-2422 A, first seen in 2002. The H₂O maser variation in flux density and radial velocity suggests that disturbances are propagating through organized structures in the form of chains ∼3.5 au long, with monotonic velocity gradients in the direction of propagation. The 18-cm OH emission in the main and satellite lines is thermal.