[IAUC] CBET 1099: 20071009 : V1280 SCORPII

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                                                  Electronic Telegram No. 1099
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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V1280 SCORPII
     U. Munari and A. Siviero, Istituto Nazionale di Astrofisica, Padova
Astronomical Observatory; A. Henden, AAVSO; and P. Ochner, C. Simoncelli,
S. Tomasoni, F. Moschini, and S. Dallaporta, ANS (Asiago Novae and Symbiotic
stars) collaboration, report that the nova V1280 Sco is steadily regaining
brightness after a prolonged faint state during its advanced decline.
Discovered around magnitude 9.7 on Feb. 4.85 UT (cf. IAUC 8803), V1280 Sco
peaked in brightness on Feb. 16 (cf. IAUC 8807, 8809); on that date, Munari
et al. measured B = 4.75, B-V = +0.51, V-R_c = +0.34, V-I_c = +0.70 with
respect to the B/V/R_c/I_c photometric sequence calibrated by Henden and
Munari (2007, IBVS 5771).  An initial slow decline turned into a rapid
decline eleven days past maximum, taking the nova from B = 7.07, B-V = +0.20,
V-R = +1.04, and V-I_c = +1.29 on Mar. 2.49 to B = 13.25, B-V = +0.22, V-R =
+1.28, and V-I_c = +2.00 on Mar. 20.44, according to their measurements.  The
nova then continued to decline at a slower rate and with an irregular pattern
until a minimum brightness was reached around 80 days past maximum:  in the
first week of May, B = 15.18, B-V = +0.69, V-R = +1.25, and V-I_c = +2.37.
This was followed by a re-brightening phase lasting a month, which peaked at
B = 13.31, B-V = +1.08, V-R = +1.20, and V-I_c = +2.51 on May 22.  The
following two months (between June 18 and Aug. 18) were spent by the light
curve of V1280 Sco being in a flat and faint state characterized by mean
values B = 17.0, V-R = +1.1, V-I_c = +1.5, and B-V increasing from +0.7 to
+1.4.  After this faint state, the nova is on the rise again, gaining 2.4 mag
in B in twenty-six days.  On Sept. 12.8, B = 15.50, B-V = +1.65, V-R = +1.03,
V-I_c = +1.94, while on Oct. 8.74, B = 13.11, B-V = +1.19, V-R = +0.87, V-I_c
= +1.51.  Spectroscopic observations of this unexpected large re-brightening
are encouraged.


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                         (C) Copyright 2007 CBAT
2007 October 9                   (CBET 1099)              Daniel W. E. Green