An optical/infrared outburst in the exciting source of HH 7-11

Abstract

An outburst of SVS 13, the excitation source of Herbig-Haro objects 7-11, is reported. The brightness at 6740 A of this source was found to have increased by around 2.5 mag sometime between December 1988 and September 1990. Since then, the source has been constantly brightening by 0.06 mag per month. A similar outburst was observed in the V, R, and I, although the amplitudes decrease with increasing wavelength throughout the infrared from Delta-H of about 1.9 mag to Delta-N of about 0.35 mag. Emission lines typical of a strong-emission T Tauri or Herbig-Ae star are found. Infrared spectra around 2.3 microns obtained in October 1986 and December 1990 show no changes in the equivalent widths of the CO emission band heads of 2-0 and 3-1. It is concluded that this outburst is similar to those observed in some T Tauri stars but is definitely not of the FU Orionis type.