Central Bureau for Astronomical Telegrams
IAUC 3667: SN IN NGC 2268; NGC 2346; 2S 1553-542; 1981j
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Read IAUC 3668
Circular No. 3667
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
SUPERNOVA IN NGC 2268
P. Wild, Astronomical Institute, Berne University, telexes
that he has discovered a sppernova 23" east and 18" north of the
nucleus of NGC 2268 (R.A. = 7h00m.8, Decl. = +84o28', equinox 1950.0). On
Feb. 12 the supernova was of photovisual magnitude 14.0.
NGC 2346
L. Kohoutek, Hamburg Observatory, reports that his UBV
photoelectric observations at the European Southern Observatory reveal
drastic changes in the brightness of the nucleus of the planetary
nebula NGC 2346. Three recent V magnitudes are: Jan. 26, 12.6;
Feb. 2, 11.3 (maximum); Feb. 10, 13.3 (diaphragm 22"). The lightcurve
was smooth between these dates. Details will be published in
the IBVS (Budapest).
2S 1553-542
R. L. Kelley, S. Ayasli and S. Rappaport, Massachusetts Institute
of Technology, report the detection of 9.3-s x-ray pulsations
from the galactic x-ray source 2S 1553-542 (Apparao et al. 1978,
Nature 271, 225). The data were obtained with the SAS-3 rmc detectors
in 1975 June. The source had an intensity of 27 uJy (2-11 keV)
with a pulsation amplitude of ~ 80 percent. The pulsations, coupled
with the object's hard x-ray spectrum and apparently transient
nature - it was not detected by Uhuru - are possibly indicative of
a Be-star x-ray binary (Rappaport and van den Heuvel 1982, IAU Symposium
No. 98, in press). No optical counterpart has yet been identified.
Optical observers are therefore urged to carry out spectroscopic
observations of the brighter stars in the small x-ray error
box of Apparao et al. (loc. Cit.) during the current observing
season.
PERIODIC COMET SWIFT-GEHRELS (1981j)
Further total visual magnitude estimates: 1981 Dec. 4.75 UT,
12.1 (G. M. Hurst, Wellingborough, Eng., 0.26-m reflector, difficult
in moonlight); Dec. 13.12, 11.3 (C. Spratt, Victoria, BC, 0.20-m
reflector); 20.13, 12.2 (Spratt); 31.00, 9.9 (J. Bortle, Stormville,
NY, 0.32-m reflector); 1982 Jan. 12.98, 11.0 (Bortle); 20.99,
11.0 (Bortle); 28.01, 11.5 (C. Morris, Harvard, MA, 0.25-m refl.).
1982 February 16 (3667) Brian G. Marsden
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