[IAUC] CBET 1761: 20090411 : V1413 AQUILAE

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                                                  Electronic Telegram No. 1761
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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V1413 AQUILAE
     U. Munari, A. Siviero, P. Ochner, and M. Valentini, Istituto Nazionale
di Astrofisica, Padova Astronomical Observatory; and S. Dallaporta, "Asiago
Novae and Symbiotic Stars" (ANS) collaboration, report that the symbiotic
nova V1413 Aql, on egress from the eclipse of the white dwarf by the M5 III
cool-giant companion (center of eclipse on Mar. 7, orbital period 434.1 days;
cf. Munari 1992, A.Ap. 257, 163), is not leveling off at the constant
magnitude (V = 13.5) that it has been keeping outside of eclipses over
the last several years; it is instead on a linear rise in brightness (0.07
mag/day), characterized by the following values for the last few days:  Apr.
4.114 UT, V = 13.295, B-V = +0.915, V-I_c = +2.113, R_c-I_c = +1.156; Apr.
8.108, V = 12.994, B-V = +0.923, V-I_c = +1.897, R_c-I_c = +1.031; Apr.
10.104, V = 12.906, B-V = +0.936, V-I_c = +1.854, R_c-I_c = +1.003.  V1413
Aql (= AS 338) entered in 1978 its still-ongoing outburst, characterized by
two maxima at V = 11 around 1982-1983 and 1995-1996 (cf. IAUC 6151, 6165) and
very slow declines thereafter to V = 13.5 (which is two magnitudes brighter
than the long-term pre-outburst quiescence value of V = 15.5 (cf. Siviero et
al. 2007, Baltic Astronomy 16, 55).  The current new rise in brightness
could mark the beginning of a long ascent to a third maximum that,
extrapolating from the previous two, could be reached at V = 11 in about
one year.  Early signs of a reprisal in brightness can be glimpsed in the
VSNET and AAVSO data collected at the end of 2008.  The present phase is
monitored with the high- and low-resolution Boller & Chievens and echelle
spectrographs of the Asiago 1.22-m telescope of the University of Padova and
the INAF 1.82-m telescope of the Astronomical Observatory of Padova.  The
spectral appearance is identical to that of the initial 1993 rise to its
1995-1996 maximum (cf. IAUC 5884).  In the last spectrum taken on 2009
Apr. 9.11, the H_beta flux was 6.76 x 10**(-13) erg cm**(-2) s**(-1), and
the flux ratio (H_beta):([O III] 500.7-nm):(He I 587.6-nm):(He II 468.6-nm)
was 1.00:0.73:0.42:0.12.  Gaining in experience from the previous two maxima
of V1413 Aql, a new maximum should be characterized by a doubling of this
H_beta flux and the above flux ratio changing to 1.00:0.15:0.35:0.00.


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                         (C) Copyright 2009 CBAT
2009 April 11                    (CBET 1761)              Daniel W. E. Green