[IAUC] CBET 620: 20060912 : Z ANDROMEDAE AND AG DRACONIS

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                                                  Electronic Telegram No. 620
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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Z ANDROMEDAE AND AG DRACONIS
      T. Iijima, Astronomical Observatory of Padova, Asiago,
reports that, in the course of the monitoring of spectral
variations of symbiotic stars, significant changes of Z And and
AG Dra were found in their recent spectra.
     The symbiotic star Z And may have entered in the outburst
stage in June 2006 (see AAVSO photometric data on this star at
http://www.aavso.org/vstar/).  High-dispersion spectra of Z And
were taken on Sept. 1.09 and 2.12 UT with an echelle spectrograph
mounted on the 1.82-m telescope at Mount Ekar.  The spectra show
that the emission line of He II 468.6-nm is fairly weakened, with
its intensity relative to that of H-beta being 0.08, which was
about 0.5 in February, and the Raman emission line at 683 nm has
disappeared.  High-velocity emission wings are detected in the
emission lines of H-alpha and H-beta.  The radial velocities of
the blue and red emission wings relative to the main emission
bodies are -1330 km/s and +1140 km/s.  On the other hand,
P-Cyg-type absorption components, blueshifted by about -100
km/s, are seen in the emission lines of He I and in H-beta and the
higher numbers of Balmer lines.  These spectral features were not
seen on the spectra taken in and earlier than Feb. 2006.
     The recent brightening of AG Dra apparently started in early
July (e.g., see CBET 577).  High-dispersion spectra of AG Dra were
taken with the same instruments on Aug. 31.87 and Sept. 1.86.  The
Raman emission line at 683 nm has disappeared, and the emission
line of He II 468.6-nm has weakened, its intensity relative to
that of H-beta being about 0.4 (having been 0.5 in April).
Wide-spread, weak emission tails, whose full width at zero
intensity is about 3000 km/s, are noticed in H-alpha, H-beta, and
probably He II 468.6-nm, while the emission lines of He I are
accompanied by P-Cyg-type absorption components, which were not
seen on the spectra taken in and earlier than April 2006.  The
blueshifts of the absorption components are -120 km/s for He I
587.6-nm and -90 km/s for He I 447.1-nm.


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                         (C) Copyright 2006 CBAT
2006 September 12                (CBET 620)               Daniel W. E. Green