Electronic Telegram No. 633
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)
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BF CYGNI
     T. Iijima, Astronomical Observatory of Padova, Asiago, reports
that, in the course of the monitoring of spectral variations of symbiotic
stars, high-dispersion spectra (range 427-596 nm) of BF Cyg were taken
on Aug. 30.9 and 31.9 UT with an echelle spectrograph mounted on the
1.82-m telescope at Mount Ekar.  The present outburst of this object
started at the end of July 2006 (CBET 596).  The last spectrum in
quiescence was taken on Apr. 8.1 with the same instruments.  Comparing
with the spectrum in the variable's quiet stage, the emission lines of
Fe II, Cr II, and Ti II have significantly strengthened, while the
intensity of the nebular line [O III] 500.7-nm decreased from 72 on
Apr. 8.1 to 6 on Aug. 30.9, where the intensity of H_beta is taken to be
100.  The emission line of [O III] 436.3-nm has nearly disappeared in the
recent spectra.  P-Cyg-type absorption components have appeared on the
lines of H I, He I, Fe II mult. 42, and Na I D1 and D2.  The blueshifts
of the absorption components were found to range from -57 km/s for Fe II
516.9-nm to -145 km/s for He I 587.6-nm, and that of H_beta was about -70
km/s.  Some spectral changes were noticed also between Aug. 30.9 and
31.9:  The intensity of the emission line of He II 468.6-nm relative to
H_beta (= 100) was about 4 on Aug. 30.9, which was still < 7 on Apr. 8.1.
This emission line, however, strengthened during only one day, and its
intensity had risen to 18 on Aug. 31.9; the absorption components of the
lines of Fe II mult. 42 disappeared at the same time, those of the other
lines being nearly the same.  Some significant changes seem to have
occurred in this object at that time.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2006 CBAT
2006 September 20                (CBET 633)               Daniel W. E. Green