This star is a binary consisting of a Wolf-Rayet star
and an O star, with orbital period of about
In the late summer of 1994 the star underwent an outburst: it brightened by about a magnitude in visible light, and emission lines which indicate expanding gas appeared in the spectrum. (See IAU Circulars 6099 & 6102.) This seems to be caused by one of the stars (probably the W-R) blowing off some more gas than usual.
WUPPE and HUT obtained a simutaneous observation, and WUPPE made three
more observations by offsetting to it while HUT was observing
three targets in the cluster NGC346 about 3' away.