Long- and short-term variability of the T Tauri star RY Lupi.

Abstract

Data are presented on spectroscopic and photometric observations of the T Tauri star RY Lupi carried out since 1981 from the FUV to the IR spectral region. These data show a remarkable kind of variability of the RY Lupi. Namely, the FUV and the IR fluxes, as well as the fluxes in H-alpha and H-beta are relatively constant, while the range in V magnitude is larger than 3 magnitudes. When the star fades, it first becomes redder; below V = 11.5, this trend is changed towards the blue, but with a very large spread in color for a given V. From the available data, fundamental parameters for the star and its environment were derived. The RY Lupi was found to have an IR excess luminosity of 40 percent of the total luminosity.