[IAUC] CBET 577: 20060717 : AG DRACONIS

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                                                  Electronic Telegram No. 577
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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AG DRACONIS
     S. Moretti and M. Graziani, Associazione Ravennate Astrofili
Rheyta (ARAR); and U. Munari and A. Siviero, Istituto Nazionale di
Astrofisica, Astronomical Observatory, Padova, report that --
following recent visual estimates collected by AAVSO and VSNET
indicating that the symbiotic binary and super-soft x-ray source
AG Dra is rising in optical brightness -- they obtained UBVRI CCD
photometric observations on July 14.92 UT, deriving the following
magnitudes:  U = 9.09 +/- 0.1, B = 9.53 +/- 0.04, V = 8.89 +/- 0.02,
R_c = 8.29 +/- 0.02, I_c = 7.76 +/- 0.03.  Comparing with data
obtained over the last 30 years (cf. Galis et al. 2004, Baltic
Astronomy 13, 132), the increase in brightness with respect to
quiescence values is 2.5 mag in U, 1.5 mag in B, and 1.0 mag in V.
This qualifies the current photometric state of AG Dra as one of the
most active of the last few decades.  CCD low-resolution spectroscopy
(1 nm/pix dispersion, range 430-790 nm) was also obtained on July
14.98 with the 0.42-m reflector of the ARAR observatory in Bastia
(Ravenna).  The spectra show the intensity of the He II 468.6-nm
emission line to be 0.75 that of H_beta, with a low intensity of the
682.5- and 708.8-nm emission bands of O VI Raman scattered by neutral
hydrogen.  This is reminiscent of a currently intermediate state
between the opposite types of cool and hot outbursts described for
AG Dra by Viotti et al. (2005, Ap. Space Sci. 296, 435).


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                         (C) Copyright 2006 CBAT
2006 July 17                     (CBET 577)               Daniel W. E. Green