Electronic Telegram No. 1431
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
URL http://www.cfa.harvard.edu/iau/cbat.html


V2468 CYGNI
     U. Munari and A. Siviero, Istituto Nazionale di Astrofisica, Padova
Astronomical Observatory; and P. Valisa, S. Dallaporta, G. Cherini, P. Ochner,
F. Castellani, L. Buzzi, M. Brienza, and V. Luppi, ANS ("Asiago Novae and
Symbiotic stars") collaboration, report that the nova V2468 Cyg (cf. IAUC
8927, 8928, 8936) is experiencing a large re-brightening during its current
advanced evolution.  Close to maximum brightness, on Mar. 12.10 UT, the nova
was measured at V = 8.09, B-V = +0.94, V-R_c = 0.71, V-I_c = +1.43.  Since
then, it has been showing a normal decline with superimposed rapid and
irregular fluctuations of a few tenths of a magnitude in amplitude.  A flat
minimum in brightness was reached during the period June 8 to 17, when the
nova was shining at V = 12.44, B-V = +0.44, V-R_c = +1.39, V-I_c = +1.14.
Since then, its has been steadily re-brightening, reaching V = 11.64, B-V =
+0.32, V-R_c = +1.18, V-I_c = +1.17 on July 2.91, thus with no significant
color change associated with the re-brightening.  Low-resolution spectra
obtained on July 4.91 show He I, the blend at 464.0 nm, and the Balmer
series in strong emission -- the integrated flux of H-beta amounting to
8.2 x 10**(-12) erg/cm**2/s.  [N II] 575.5-nm and [O II] 732.5-nm --
with integrated fluxes of 1.6 and 1.0 x 10**(-11) erg/cm**2/s, respectively
-- are the strongest emission lines after H-alpha.  The H-alpha emission
shows more evidently the multi-peaks profile that it has been displaying
during the last few months.  On July 5.90, the H-alpha profile was
characterized by an overall Gaussian shape with FWHM = 1430 km/s and +93
km/s heliocentric radial velocity, with major peaks at heliocentric radial
velocities -585, -345, -185, -30, +120, +300, and +630 km/s.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2008 CBAT
2008 July 7                      (CBET 1431)              Daniel W. E. Green