Optical Evolution of the Outburst of the Symbiotic Nova V4368 SGR = Wakuda's Peculiar Star

We present the complete V band light-curve of the outburst of V4368 Sgr over the 16 years elapsed since its onset in 1993, and provide also its B--V, R_C --I_C and V--I_C colors from CCD observations. Recent absolute spectrophotometry of the star is compared with earlier similar data. V4368 Sgr remained stable at optical maximum around V = 10.26 mag for four years, from 1995 to 1998, and since then very smoothly and slowly declined to V = 11.65 mag in 2009, still a whole 10 mag brighter than in quiescence, when it was below the ∼ 21.5 mag threshold of DSS-I ESO/SERC J and R plates. The spectrum over the last 15 years has kept its low ionization character, while the overall intensity of the emission lines (Balmer, He I, [O I], Fe II and [Fe II]) has increased by ∼ 10 times. This has been accompanied by a corresponding increase in intensity of the nebular continuum which has now almost overwhelmed the emission from the fading outbursting star. As at the time of maximum brightness, the emission lines in 2009 are still very sharp and with no P-Cyg absorption flanking them, indicating that mass loss from V4368 Sgr is keeping very low or absent, and no fast wind from the outbursting star has so far emerged.