CAOSP abstracts, Volume: 35, No.: 2, year: 2005

Abstract: We present the UBVRI photometry and 460-900 nm spectroscopy of a classical nova V475 Sct obtained after its outburst in August 2003. The object can be classified as a slow Fe II nova with the standstill at maximum and dust formation at later stages. The brightness declines t2,V = 48 d, t2,B = 50 d, t3,V = 53 d, t3,B = 58 d were found from our B,V light curves and corresponding absolute magnitudes of the nova at maximum MVmax = --7.16±0.15 and MBmax = -6.96±0.39 were calculated. The latter value yields a mass of 0.73±0.07 M for the white dwarf component. We determined the colour excess E(B-V) = 0.69±0.05 and the distance to the nova d = 4.8±0.9 kpc. During the standstill and on decline the 13.4-day periodicity of flares was found, the best detected in the V-I index. The rapid fade of the brightness, which started 57 days after the maximum, could be related to a dust formation in the ejecta of the nova. The early optical spectra display the forest of low ionization emission lines, primarily Fe II and H, accompanied by two P Cygni absorptions, arising in the inner and outer envelope of the expanding nova shell ejected at brightness maximum and accelerated by continuous stellar wind. The spectrum taken in the nebular stage of the nova, which started in March 2004, shows very strong emission [O III] 495.9 nm and 500.7 nm lines, responsible for discrepancy of the B and V magnitudes determined from observations taken by different instruments. The nebular emission line profiles suggest a nonspherical ejection of the shell.

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Last update: June 23, 2005