AN OPTICAL INFRARED OUTBURST IN THE EXCITING SOURCE OF HH 7-11

We report on an outburst of SVS 13-the exciting source of Herbig-Haro objects 7-11. According to our CCD archives and recently obtained CCD images, the brightness at 6740 angstrom of this source increased by around 2.5 mag sometime between 1988 December and 1990 September. Since then, the source has been constantly brightening by 0.06 mag per month. A similar outburst was observed in V, R, and I, although the amplitudes decrease with increasing wavelength throughout the infrared from DELTA-H approximately 1.9 mag to DELTA-N approximately 0.35 mag. In our optical spectra, taken in 1989 November and 1990 November, we find emission lines typical of a strong-emission T Tauri or Herbig-Ae star. Infrared spectra around 2.3-mu-m obtained in 1986 October and 1990 December show no changes in the equivalent widths of the CO emission band heads nu = 2-0 and nu = 3-1. We conclude that this outburst, as far as we can ascertain, is similar to those observed in some T Tauri stars (e.g., EX Lupi), but-at least thus far-is definitely not of the FU Orionis type.