1997A&AS..126...91T

We present optical and IR photometry, optical multi-dispersion spectroscopy, and IR spectrophotometry of the FU Ori variable Z Canis Majoris, obtained in the years 1984, 1985, 1989 and 1996. A comparison of data obtained in 1984 and 1985 confirms that in 1985 Z CMa underwent a low-power eruption. The enhancement of Hα emission line, the transition of Hβ and Feii lines from pure absorption to emission with or without a P Cygni profile, the appearance of the Hei 6678Å absorption line, a radial velocity increase of about 30% of the P Cygni absorption components, and finally a 0.2-0.3mag increase of IR luminosity, were all dinstinctive characteristics of this state. Further observations in 1996 show that Z CMa is in a low-luminosity state at V=10.24 while the appearance of a double-peaked Hα emission, with the blue component much weaker than the red one, is the most significant spectroscopic variation. Energy distributions in the range 0.4-5µm, obtained during 1984 and 1985 observational runs, are also presented.