[IAUC] CBET 2034: 20091121 : V496 SCUTI

[IAUC mailing list]

                                                  Electronic Telegram No. 2034
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS en CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT en CFA.HARVARD.EDU (science)
URL http://www.cfa.harvard.edu/iau/cbat.html


V496 SCUTI
     U. Munari and A. Siviero, Istituto Nazionale di Astrofisica, Padova
Astronomical Observatory; and P. Valisa, S. Dallaporta, and L. Baldinelli,
Asiago Novae and Symbiotic Stars (ANS) collaboration, report that a tight
monitoring of Nova Sct 2009 has been carried out daily since announcement of
its discovery (cf. IAUC 9093).  The nova has displayed a steady rise toward
maximum, which was reached around Nov. 19.2 UT at B = 7.86, B-V = +0.76,
V-R_c = +0.50, V-I_c = +1.02.  The latest measurement on Nov. 20.7 gives B =
8.01, B-V = +0.71, V-R_c = +0.49, V-I_c = +1.02.  It took 8.0 days for the
nova to rise the final 1 mag in brightness toward maximum.  Low-resolution
absolute spectrophotometry (range 390-860 nm, dispersion 0.21 nm/pixel) and
high-resolution echelle spectroscopy (resolving power 20000, range 395-865
nm) has been obtained with the Asiago 1.82-m and Varese 0.6-m telescopes at
various dates, showing that the nova has significantly changed its spectral
appearance while rising toward maximum.  On Nov. 19.8 and 20.8 UT, the spectra
are still dominated by Balmer and Fe II emission lines, as they were at the
time of discovery (cf. IAUC 9093), with now also strong Na I, Ca II (393,
397, 849, 854, 866 nm), and O I (777 and 845 nm).  All emission lines present
similar and highly structured P-Cyg profiles.  The broad and single absorption
component, which dominated the P-Cyg profile at the time of discovery, is now
replaced by two much-sharper components.  For the Fe II multiplet-42 lines,
the two absorptions are located at heliocentric velocities of -785 and -360
km/s, and their FWHM are 260 and 90 km/s, respectively.  Also, the FWHM of the
emission lines has decreased, now being 600 km/s.  The H_alpha:H_beta:H_gamma:
H_delta integrated emission flux ratio is now 3.05:1.00:0.35:0.23, flatter than
at the time of discovery, and that of O I 777.2/844.6 has reversed to 1.18.
The integrated flux of the H_beta emission has increased from 3.0 x 10**(-11)
erg cm**(-2) s**(-1) on Nov. 9.8 to 1.1 x 10**(-10) erg cm**(-2) s**(-1) on
Nov. 19.8.
     Visual magnitude estimate by K. Hornoch, Vohancice, Czech Republic:
Nov. 19.726 UT, 7.2.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2009 CBAT
2009 November 21                 (CBET 2034)              Daniel W. E. Green