Nova Cygni 2001/2 = V2275 Cyg

Abstract

We present an analysis of low- and medium resolution spectra of the very fast nova, Nova Cygni 2001/2 (V2275 Cyg) obtained at nine epochs in August, September and October, 2001. The expansion velocity from hydrogen Balmer lines is found to be 2100 km/s, although early H-alpha profile showed a weak feature at -3500 km/s, too. The overall appearance of the optical spectrum is dominated by broad lines of H, He and N, therefore, the star belongs to the ``He/N'' subclass of novae defined by Williams (1992). Interstellar lines and bands, as well as BV photometry taken from the literature yielded to a fairly high reddening of E(B-V)=1.0+/-0.1 mag. The visual light curve was used to deduce M_V by the maximum magnitude versus rate of decline relationship. The resulting parameters are: t_0=2452141.4(+0.1)(-0.5), t_2=2.9+/-0.5 days, t_3=7+/-1 days, M_V=-9.7+/-0.7 mag. Adopting these parameters, the star lies between 3 kpc and 8 kpc from the Sun.