A Predicted Great Dimming of T Tauri: Has it Begun?

Abstract

The optical star in the T Tauri triple system is the prototype of young sun-like stars in our galaxy. This complex and dynamic system has evidence for misaligned disks and outflows, and molecular material in a circumbinary ring that obscures the southern infrared binary, T Tau South. Observations by members of the American Association of Variable Star Observers (AAVSO) show that T Tau North, the optical star, has dimmed by up to ~2 magnitudes in the visual over the course of the past decade. The dimming across the B, V, R and I bands has a color character typical of changes in ISM extinction, suggesting an increase in obscuration along the line of sight to T Tau North. Material associated with the circumbinary ring around T Tau South has been predicted to occult the optical star via wide-scale orbital motion of the system. Through analysis of the geometrical configuration and motion of dust structures in the system, it seems that a great dimming of T Tau North by line-of-sight material associated with the T Tau South binary has, in fact, begun. Based on the extent and motion of the circumbinary ring material associated with the southern binary, T Tau North will likely experience dimming events for decades to come and may disappear entirely from the optical sky as the densest mid-plane region of the ring traverses our line of sight.