This weeks light curve is of the star TX Ori. The object is part of the sigma-Ori cluster and known as a variable star of Orion type, which means it shows erratic, more or less random variations in it’s brightness. Given the light curve data we have gathered over the past five observing seasons, this description is certainly valid. Indeed the behaviour is what one could describe as the archetypal T Tauri star. The object varies in all filters by at least one magnitude. There seems to be a general dimming trend of the source over the past two years, with the maximum brightness getting fainter each year.
This star is one of the targets of the new Hubble Space Telescope Legacy Program Ullyses that aims to take ultraviolet spectra of a number of young stars. This is a very large program with approximately 1000 orbits. The data taking for the T Tauri stars in this program will start this autumn. We aim to get involved in this project by providing simultaneous/contemporaneous photometric monitoring of the stars. We will keep you updated on our plans for this in the near future.