Nova V2362 Cygni rapidly changes spectrum
ATel #963; Kimeswenger, S., Dalnodar, S., Knapp, A., Schafer, J., Unterguggenberger, S., Weiss, S. (AI Innsbruck)
on 14 Dec 2006; 22:53 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Stefan Kimeswenger (Stefan.Kimeswenger@uibk.ac.at)
V2362 Cygni (N Cyg 2006) had the outburst end March or early April
2006 (Nakano, IAUC 8697 ) and the maximum April, 6th. After a rapid
decline (t3 = 19 days) it stopped its decline 4.5 mag below maximum
and thereafter re brightened (Goranskij et al. ATEL #928). After
V2362 Cygni (N Cyg 2006) concluded it's re brightening (2.0 mag)
phase (Munari et al. CBET 769) it started a rapid decline 7 months
after maximum. While the spectroscopy during the plateau changed
marginally the P-Cygni absorption changed its velocity to values
during main outburst (Munari et al. CBET 769). It was classified as
Fe II-type CO novae (Russell et al. IAUC, 8710). While our spectrum
obtained December, 7th still is dominated by the NII+[NII] blend on
570.8nm, NaI+OI blend on 592.0nm (FWHM approx 80A) and H_alpha (FWHM
= 6.8nm) and tiny P-Cygni absorptions, the spectra obtained December
13th and 14th with the Innsbruck 60cm telescope, are dominated by
narrow , but higher, Balmer lines (H_alpha FWHM = 3.4nm) and [NII]
(567.6 nm, FWHM = 3.3nm). Weak emission of [OII] 630.0nm, 731.8nm
and 732.9nm and [OI] 844.6 nm are also visible. The continuum
dropped dramatically towards detection limit - line contrast H_alpha
/ continuum changed from 3:1 to 35:1. Although the nebular stage clearly
started, excitations states of dominating lines still is very low.
Continuous spectroscopic monitoring is required.
The spectrum is given at http://astro.uibk.ac.at/60cm/V2362Cyg.jpg
