Analysis of MOST light curves of five young stars in Taurus–Auriga and Lupus 3 star-forming regions

Continuous photometric observations of five young stars obtained by the MOST satellite in 2009 and 2010 in the Taurus and Lupus star formation regions are presented. Using light-curve modelling under the assumption of internal invariability of spots, we obtained small values of the solar-type differential-rotation parameter (k = 0.0005–0.009) for three spotted weak-line T Tauri stars, V410 Tau, V987 Tau and Lupus 3-14; for another spotted weak-line T Tauri star (WTTS), Lupus 3-48, the data are consistent with a rigidly rotating surface (k = 0). Three flares of similar rise (4 min and 30 s) and decay (1 h and 45 min) times were detected in the light curve of Lupus 3-14. The brightness of the classical T Tauri star RY Tau continuously decreased over 3 weeks of its observations with a variable modulation not showing any obvious periodic signal.