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

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 Hα 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.

The Inner Disk of RY Tau: Evidence of Stellar Occultation by the Disk Atmosphere at the Sublimation Rim from K-band Continuum Interferometry

“…This is in stark contrast to the highly inclined (i d ∼60°-70°) disk observed by CARMA (Isella et al 2010) and ALMA (Long et al 2018(Long et al , 2019Pinilla et al 2018). A more highly inclined inner disk is also supported by the nature of the optical and IR photometric variability exhibited by RY Tau, which is likely to arise due to line of sight occultation of the stellar photosphere by circumstellar material (Grankin et al 2007;Petrov et al 2019).…”

“…As RY Tau is variable across optical and NIR wavelengths (e.g., Grankin et al 2007;Petrov et al 2019) 3). As our interferometric data were , )-plane coverage of the compiled K-band interferometry.…”

“…From the top panel of Note. For the "Herein" row, T eff , M å , and log g are from Calvet et al (2004); d from Kenyon et al (1994), Galli et al (2018); and A V from Petrov et al (2019).…”

“…T eff and M å are taken from Calvet et al (2004), while we revise their estimate of the stellar luminosity, L å , using the "bright" epoch photometry and A V from Petrov et al (2019).…”

Классические Звезды Типа Т Тельца: Аккреция, Ветер, Пыль

“…Это позволяет определить потоки излучения в эмиссионных линиях в абсолютных единицах, что бывает полезным при интерпретации полученных данных. Результаты этого мониторинга за первые пять сезонов (2013-2018) опубликованы в Petrov et al (2019). В качестве примера на рис.…”