BVI photometry and the spectroscopy of Nova Scuti 2005 N.2

¹ INAF Osservatorio Astronomico di Padova, via dell'Osservatorio 8, 36012 Asiago (VI), Italy e-mail: munari@pd.astro.it
² via Filzi 9, 38034 Cembra (TN), Italy

Received: 19 December 2005
Accepted: 7 March 2006

Abstract

Our CCD photometry of Nova Scuti 2005 N.2 (=V477 Sct) shows it to be a very fast nova, which is characterized by t₂ = 3 and t₃ = 6 days, affected by a E_B-V ≥ 1.3 mag reddening, and which peaked at V ~ 9.8 mag on ~Oct. 12.0 UT. The nova was probably entering a dust condensation episode or brightness oscillations during the transition phase when it became unobservable for the seasonal conjunction with the Sun. Absolute spectrophotometry shows it to belong to the He/N class. The emission line width at half intensity is 2600 km s^-1. At least five ripples are identified in the high resolution emission lines profiles at radial velocities ranging from -980 to +700 km s^-1. The nova erupted at a large distance from the Sun and at an appreciable height above the Galactic plane, suggesting an association with the Galactic bulge (unusual for a He/N nova). The progenitor was too faint to be recorded on DSS1/2 survey plates, when setting the outburst amplitude to  ≥ 11 mag.