Institution(s): 1. Shamakhy Astrophysical Observatory
Based on many years of observational data from a photometric database on young stars, we propose a new classification scheme for the light curves of classical T Tauri stars. Our analysis of the combined light-curve shapes for 28 classical T Tauri stars is used to distinguish up to five light-curve types. The proposed scheme suggests a qualitative interpretation in terms of interaction of the central star with its circumstellar accretion disk.
The main element – quick time daily variability - is observed in all types of light curves. The simplest light curve is a type I which can be described in a model of sustainable cold spots, and subsequent types of light curves are complicated in a shape with increasing number type. Variable stars with light curves of type I by our classification (constant mean brightness and constant amplitude) will likely not be explained by accretion of matter from the circumstellar disk, because the rate of accretion of matter onto the star in general cannot be permanent. This type variability in light curves can be explained by the presence of cold spots and the existence of an active star chromosphere.
There is 82% correlation level between amplitudes of light curves of T Tauri stars in the active and quiet conditions.
According to the amplitude distribution of light variation patterns in the different quantity of stars were similar, which indicates that the main physical nature of light variations in the young stars is common.