Central Bureau for Astronomical Telegrams
IAUC 3316: SNe; N Cyg 1978
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Circular No. 3316
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 617-864-5758
SUPERNOVAE
R. P. Kirshner, University of Michigan, reports that spectro-
photometry by W. P. Blair at the McGraw-Hill Observatory on Nov. 30
and Dec. 1 shows that Wild's probable supernova in NGC 3780 (IAUC
3303) is a type II supernova, probably well past maximum light.
The object reported by Lovas (IAUC 3305) does not have a normal
supernova spectrum. On Nov. 29 the spectrum showed two strong features:
H-beta and H-alpha redshifted by ~ 4500 km/s, and a relatively smooth
continuum. The H-alpha line had a full width at zero intensity of
12 000 km/s. Further spectrophotometry of these objects is planned.
Photometry would be very useful.
S. M. Simkin, Siding Spring Observatory, reports the following
photoelectric measurements, obtained by E. Sadler and herself on
Nov. 30.35 UT of the supernova in IC 5201 (IAUC 3309): V = 12.86 +/-
0.07, U-V = +0.67 +/- 0.14, B-V = +0.37 +/- 0.08, V-R = +0.27 +/- 0.08,
V-I = +0.28 +/- 0.15. Colors are in the Kron-Cousins system, with
filters described by Bessell (1976, Publ. Astron. Soc. Pacific 88,
557). The 100-cm telescope was used; the seeing was very poor.
NOVA CYGNI 1978
G. Giuricin, F. Mardirossian, M. Mezzetti, M. Pucillo, P.
Santin and G. Sedmak, Trieste Astronomical Observatory, communicate:
"High-speed (sampling time 0s.01) unfiltered photoelectric observations
were made on Sept. 13, 14, 15, 20 and 21 with a twin-beam
photometer. Rapid flickering up to frequencies of 5 Hz (percent
standard deviation 0.1-0.5) were found, variable within every night
and from night to night. Power-spectrum analysis revealed no stable
periodicity in the brightness variation. There is strong evidence
of short-lived quasi-monochromatic oscillations on Sept. 14
at 15 Hz, and at 81 Hz (or higher-order harmonic) oscillations lasting
100-200 s were found; on Sept. 15 at 0.19 Hz oscillations displayed
decreasing amplitude with time and lasted about 500 s."
T. E. Margrave, University of Montana, revises his measurements
on IAUC 3281 as follows: Sept. 19.328 UT, V = 7.71, B-V =
+0.18, U-B = -0.63; 20.297, 7.79, +0.18, -0.57; 24.275, 8.34, +0.18,
-0.64; 27.205, 8.30, +0.21, -0.66; 30.301, 8.68, +0.22, -0.68.
Measured rather than assumed colors were adopted for the comparison
stars HR 8272 and SAO 51226, and the latter star has been found to
have V = 8.68 rather than thc assumed V = 8.30.
1978 December 22 (3316) Brian G. Marsden
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