The 1993-1994 activity of EX Lupi

EX Lupi is a classical T Tauri star (and the EXor prototype) subject to spo radic outbursts. The historic record shows that it remains at about V = 13. 2 (or m(pg) = 14.7:) for extended periods, from which it has been observed to brighten to as much as V = 8.4 (on one occasion in 1955-1956). During 19 93-1994 the star remained slightly above normal minimum, at about V = 12.8, and from that level rose to three maxima at V = 11.4 and on other occasion s to about V = 12.0. At minimum light an M0 V absorption spectrum is presen t. At outburst this spectrum is veiled by a hot continuum (well shown by an IUE exposure), the equivalent widths of the optical-region emission lines decrease, and reverse P Cygni absorption components appear at the higher Ba lmer lines. The outbursts are believed to be due to episodic infall onto th e M0 star.