THE ASTRONOMER Electronic Circular No 68 1987 Oct 05 1957.UT.
Telecom Gold 72:MAG60138
Ed:Guy M Hurst, 16, Westminster Close, Kempshott Rise, Basingstoke,
Hants, RG22 4PP, England. Telephone:(0256)471074.Int:+44256471074
Telex:265871(MONREF G) Quote"7COMET BRADFIELD (1987s)
The parabolic orbital elements on MPC 12309 (from observa-
18 16 39.23 - 6 01.7
20 16 45.71 - 5 17.7 1.245 0.931 5.7
6 5E 1984 No. 2)
Visual magnitude estimates: Sept. 14.8 UT, 12.7 (A. Mizser,
Budapest, Hungary); 16.02, 12.3 (P. Schmeer, Bischmisheim, West
Germany); 29.98, 12.3 (Schmeer); 30.96, 12.4 (Schmeer).
IAUC 4461
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For those of you who can understand it (gulp) the following
information has been published.
SUPERNOVA 1987A IN THE LARGE MAGELLANIC CLOUD
W. Sandie, G. Nakano and L. Chase, Lockheed Palo Alto Re-
search Laboratory; G. Fishman, C. Meegan, R. Wilson and W. Pacie-
sas, NASA Marshall Space Flight Center; and G. Lasche, DARPA, re-
port: "A balloon-borne gamma-ray spectrometer (consisting of an array
of high-purity Ge detectors, 119 cm**2, resolution 2.5 keV FWHM at
1.0 MeV, surrounded by an active NaI(Tl) collimator/Compton sup-
pressing anti-coincidence shield, nominally 10 cm thick) was flown
from Alice Springs, Australia, on May 29-30. The average slant
depth of residual atmosphere in the direction of SN 1987A at float
altitude was 6.3 g cm-2 during the observation. SN 1987A was with-
in the 22 FHWM field-of-view for about 3300 s during May 29.9-30.3 UT
(96 days after the observed neutrino pulse). No excess gamma-rays
were observed at the energies of the 56Ni/56Co decay chain or from
other lines in the energy region from 0.1 to 3.0 MeV. With 80 per-
cent of the data analyzed, the preliminary 3 sigma upper limit obtained
in a search for the 1238-keV line from 56Co at the instrument res-
olution (about 3 keV) is 1.3 x 10**-3 photons cm-2 s-1. The upper limit
scales as the square root of line width assumed in the search.
The corresponding limit for the 847-keV 56Co line is 1.7 x 10**-3
photons cm-2 s-1, owing to higher background at this energy. These
data imply that there was less than 2.5 x 10**-4 solar masses of 56Co exposed
to the earth at the time of the observation. Further analysis is
in progress using the complete data set. Additional balloon-borne
observations are planned."
Visual magnitudes by A. C. Beresford, Adelaide, S. Australia:
Sept. 29.47 UT, 5.2; 30.46, 5.2; Oct. 1.48, 5.3; 2.47, 5.2.
IAUC 4463
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PERIODIC COMET WEST-KOHOUTEK-IKEMURA (1987x)
This comet has been independently recovered by T. Seki,
Geisei, as follows:
1987 UT R.A. (1950) Decl. m1
Oct. 1.82188 10 04 59.9 +26 47 11 18
IAUC 4464
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Alan Young.