Spectral evolution of Nova V400 Per (1974) and Nova V373 Sct (1975)

Photographic and spectroscopic observations of the two galactic novae, V400 Per and V373 Sct, which appeared in 1974 and 1975, have been carried out at Asiago. The light curves of the two novae were characterized by the presence of brightness oscillations during the early decline. The spectral evolution was quite normal: the spectra showed at first, over a relatively strong continuum, wide emission bands of moderate excitation, accompanied by blueshifted absorptions, with radial velocities of ‑1760 km s^‑1 (Nova Per) and ‑1260 km s^‑1 (Nova Sct). Later, after the novae entered the nebular stage, the continuum weakened, the absorption disappeared and the novae displayed the usual emission spectrum, with permitted and forbidden lines of high excitation ([OIII], NIII, HeI, HeII). Forbidden lines of FeVI and FeVII-and in Nova Sct, also FeX and AX-were present for a time, but they soon disappeared, so that at the end the spectrum was dominated by the [OIII] nebular lines, even stronger than Hα.