Central Bureau for Astronomical Telegrams
IAUC 4277: GK Per
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Circular No. 4277
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-495-7244/7440/7444
GK PERSEI
A. Bianchini, Padua Observatory, telexes: "Coordinated
optical, infrared and ultraviolet observations of GK Per during the
recent optical outburst were made at Vilspa, Asiago, Padua, Trento
and Tirgo. Spectroscopic observations made by F. Sabbadin, T.
Iijima, M. Turatto and E. Cappellaro at Asiago on Nov. 24, 25, 26
and Dec. 1 show a strong blue continuum with prominent emissions
of H, He I, He II and N III; in particular, the He II 468.6 nm/H beta
intensity ratio is greater than unity and varies together with the
intensity and slope of the continuum on a timescale of 30 min.
High-speed photometry performed by R. Stagni and A. Bianchini on
Nov. 24, 25 and 27 using the rapid photometer at Asiago shows that
the U lightcurve of the nova is characterized by a rapid flickering
(Delta-m about 0.1 mag) on a timescale of 40-400 s; also by a longer-term,
stronger modulation (delta m = 0.3-0.5 mag) on a timescale of 1000-3000
s. Fourier analysis of the data revealed no stable periodicity in
the range 4-500 s. Continuous photographic monitoring of the nova
secured by G. Favero, F. Fiamoi, G. A. Milani and A. Tonello with
the 0.40-m reflector of the G. Colombo Observatory, Padua, showed
that in the time interval Nov. 25.900-25.916 UT the magnitude
varied between 10.8 and 11.3 on a timescale of a few min; during
Nov. 26.875-26.948 the visual magnitude varied between 11.3 and
11.5 on a timescale of 30 min. Simultaneous UBVR photographic
observations obtained by I. Dalmeri with a set of 18/10 Schmidt
telescopes give the following results: Nov. 6.95, V = 12.8, B-V =
+0.45; 24.87, V = 11.47, B-V = +0.10, U-B = -0.62, V-R = +0.47;
30.83, B = 11.35, U-B = -0.85; 30.85, V = 11.35, B-V = +0.10;
30.89, V = 10.90, V-R = +0.55. UBV plates taken with the Asiago
0.92-m and 0.50-m Schmidt telescopes give the following B
estimates: Nov. 3.87, 13.9; 24.75, 11.7; 24.78, 11.7; 25.68, 11.45;
29.91, 11.5; 30.81, 11.2; Dec. 1.87, 11.3; U estimates: Nov.
24.80, 11.2; 30.86, 11.0; and V estimates: Nov. 24.82, 11.2;
25.84, 11.1; 29.92, 11.0; 30.79, 11.0; Dec. 1.89, 10.8. Since the
outburst started on Nov. 6 (+/- 2), it occurred 1235 +/- 4 days after
the start of the 1983 outburst. This confirms the expectations of
the semiperiodicity found by Sabbadin and Bianchini (1983, A.Ap.
Suppl. 54, 393); see also Bianchini et al. (1986, A.Ap. 160, 367)."
1986 December 5 (4277) Brian G. Marsden
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