Idiomas

Dynamics of wind and the dusty environments in the accreting T Tauri stars RY Tau and SU Aur

Petrov, P. P.; Grankin, K. N.; Gameiro, J. F.; Artemenko, S. A.; Babina, E. V.; de Albuquerque, R. M. G.; Djupvik, A. A.; Gahm, G. F.; Shenavrin, V. I.; Irsmambetova, T. R.; Fernandez, M.; Mkrtichian, D. E.; Gorda, S. Yu.
eprint arXiv:1811.08635
11/2018

ABSTRACT

Classical T Tauri stars with ages of less than 10 Myr possess accretion discs. Magnetohydrodynamic processes at the boundary between the disc and the stellar magnetosphere control the accretion and ejections gas flows. We carried out a long series of simultaneous spectroscopic and photometric observations of the classical T Tauri stars RY Tau and SU Aur with the aim to quantify the accretion and outflow dynamics at time scales from days to years. It is shown that dust in the disc wind is the main source of photometric variability of these stars. In RY Tau we observed a new effect: during events of enhanced outflow the circumstellar extinction gets lower. The characteristic time of changes in outflow velocity and stellar brightness indicates that the obscuring dust is near the star. The outflow activity in both stars is changing on a time scale of years. Periods of quiescence in H$\alpha$ profile variability were observed during 2015-2016 season in RY Tau and during 2016-2017 season in SU Aur. We interpret these findings in the framework of the magnetospheric accretion model, and discuss how the global stellar magnetic field may influence the long-term variations of the outflow activity.