The 1989 outburst of the recurrent nova V745 Sco.

Optical and infrared observations of the 1989 outburst of the recurrent nova V745 Scorpii are reported. The outburst characteristics of the nova, rapid rise to maximum (<0.5 d), fast decline (τ₂ =5 d) and general spectral evolution, closely resemble those of RS Oph and T CrB, the only other recurrent novae with M-type secondaries. The outburst development was very fast, fading to quiescence after only two months. The post-outburst infrared colours and the galactic position of the object strongly suggest that the M star in V745 Sco is of the low-luminosity type found in the Galactic Bulge. The measured magnitudes are consistent with V745 Sco being at the distance of the Galactic Centre. In fact this establishes the distance of V745 Sco with higher accuracy than that of any other recurrent nova.