Early post-maximum spectral evolution of the fast novae V4742 Sagittarii and V4743 Sagittarii

• Published in: Monthly notices of the Royal Astronomical Society Vol. 344; no. 2; pp. 521 - 526
• Main Authors: Morgan, G. E., Ringwald, F. A., Prigge, J. W.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 11.09.2003
• Subjects: cataclysmic variables; instrumentation: miscellaneous; line: identification; methods: observational; novae; novae, cataclysmic variables; stars: fundamental parameters
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1046/j.1365-8711.2003.06852.x

The novae V4742 and V4743 Sagittarii (Sgr) erupted less than a week apart in 2002 September. This paper collects together early IAU Circular observations, plots light curves, and presents our own spectra of these novae. The spectra were collected with equipment commercially available to amateur astronomers. We identify the major spectral emission lines, measuring full widths at half-maximum, velocity widths and equivalent widths. Both novae displayed fast Duerbeck type A light curves. The eruption of V4743 Sgr fits into the spectral classification scheme for novae proposed by Williams et al. with a principal Fe ii spectrum giving way to an auroral spectrum. We observed only the principal Fe ii phase in V4742 Sgr, during which its He i 706.5-nm emission line appeared early then faded along with the Fe ii complex. This was unlike the spectral evolution of V4743 Sgr, in which the He i 706.5-nm line emerged after the Fe ii complex diminished.