Variability of classical T Tauri

We characterize the long term photometric variations of 49 CTTs with sufficient data for allowing a robust statistical analysis and propose an empirical classification scheme. Several patterns of long term photometric variability are identified.

The most common pattern, exhibited by a group of 15 stars which includes T Tau itself, consists of low level variability (with V-amplitude less than 0.4mag) with no significant changes occurring from season to season over many years. A related subgroup of 22 stars exhibit a similar stable long term variability pattern, though with larger amplitudes (up to 1.6mag). Besides these representative groups, we identify three smaller groups of 3-5 stars each of which have distinctive photometric properties.