Abstract:
We present the evolution of optical spectra and light curves of the fast nova V1674 Herculis during 150 d past its eruption. Using the post-eruption AAVSO light curv e, w e hav e calculat ed the orbital period of V1674 Her t o be 0.153 d. There is no unambiguous white dwarf spin period in our data. The optical spectra show that the ionization increases with time. A morphokinematic analysis of the H α line profile indicates a bipolar morphology with polar blobs and an equatorial ring. Lyman beta fluorescence is found to be the dominant mechanism for the e x citation of neutral o xy gen. On day 19.87, [N e iii ] and [Ne v ] lines are present, indicating the presence of the ONe white dwarf. On day 147.66, the nebular lines are still present, implying that the nova had not gone into quiescence yet; this spectrum is accretion-dominated.
