[IAUC] CBET 897: 20070319 : V2467 CYGNI = NOVA CYGNI 2007

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                                                  Electronic Telegram No. 897
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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CBAT en CFA.HARVARD.EDU (science)
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V2467 CYGNI = NOVA CYGNI 2007
     U. Munari, Istituto Nazionale di Astrofisica, Padova Astronomical
Observatory; and G. Dalla Via, P. Valisa, S. Dallaporta, and F. Castellani,
ANS ("Asiago Novae and Symbiotic stars") Collaboration, writes that an
absolutely fluxed optical spectrum (range 400-734 nm, resolution 0.0175
nm/pixel) of Nova Cyg 2007 (cf. CBET 890, 891; IAUC 8821) was obtained on
Mar. 18.16 UT.  Overall, the spectrum shows emissions of modest intensity
with prominent P-Cyg affecting only the Na I profile.  Most of the flux is
emitted from the relatively smooth underlying continuum.  The nova belongs
to Williams' (1992, A.J. 104, 725) 'Fe II' class, with strongest Fe II
emission lines belonging to multiplets 37, 38, 42, 48, 49, 55, and 74.
The expansion velocity derived from Fe II emission-line profiles is 900
km/s.  The integrated flux of the Fe II multiplet-42 line at 492.3 nm is
2.5 x 10^(-11) erg cm^(-2) s^(-1), and that of the multiplet-74 line at
624.6 nm is 2.2 x 10^(-11) erg cm^(-2) s^(-1).  The integrated flux of
the H_beta emission line is 6.1 x 10^(-11) erg cm^(-2) s^(-1), and the
H_alpha:H_beta:H_gamma emission ratio is 9.31:1.00:0.14.  H_alpha shows a
symmetric, gaussian-like emission profile characterized by an expansion
velocity of 910 km/s, with superimposed a sharp absorption component
centered at -913 km/s (with respect to the peak of emission component)
with a FWHM of 405 km/s (corrected for instrumental resolution) and an
equivalent width of 0.519 nm.  A much weaker absorption component is
located at -1900 km/s, FWHM = 270 km/s, and EW = 0.09 nm.  Similar
absorptions are visible in H_beta.  Diffuse interstellar bands are
observed at 442.8, 578.0 (equivalent width 0.179 nm), 579.6 (0.052),
628.4 (0.175), and 661.4 (0.030) nm.  The limited spectral resolution
allows only a preliminary estimate of the reddening:  the 0.05-nm
equivalent width of interstellar Na I D2 would correspond to E(B-V) =
0.31, following the calibration by Munari and Zwitter (1997, A.Ap. 318,
269).  CCD and photoelectric photometry for Mar. 18.15 gives V = 8.29
(+/- 0.02) and B-V = +1.52 (+/- 0.02).


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                         (C) Copyright 2007 CBAT
2007 March 19                    (CBET 897)               Daniel W. E. Green