Central Bureau for Astronomical Telegrams
IAUC 4329: 1987B; 1987A
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Read IAUC 4330
Circular No. 4329
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
SUPERNOVA 1987B IN NGC 5850
R. Kirshner and E. Schlegel, Center for Astrophysics, report
that a spectrum taken at the MMT by J. Huchra shows emission at H alpha,
beta and N III/H gamma at about 440 nm. This spectrum resembles that of
SN 1983K before it reached maximum (Niemela et al. 1985, Ap.J. 289,
52). The H alpha emission is very broad (about 9000 km/s) at FWZI. The
positional offset is confirmed to be 75" and 145" (cf. IAUC 4322).
SUPERNOVA 1987A IN THE LARGE MAGELLANIC CLOUD
R. M. West, European Southern Observatory, informs us that a
color exposure (Agfachrome 1000 RS, Hasselblad 6 x 6) of the LMC
was made by C. Madsen at La Silla during Feb. 23.042-23.056 UT.
Sanduleak -69 202 is just seen near the limiting magnitude of about 12.
J. Bahcall, A. Dar and T. Piran, Institute for Advanced
Study, Princeton, communicate the following note, prepared in
advance of the report of the neutrino detection on IAUC 4323: "We
have calculated the event rate expected in terrestrial neutrino
detectors from neutrinos produced in the formation of the neutron
star in the LMC supernova. Using neutrino fluxes from a model
stellar collapse calculation of Wilson et al. and cross sections
from Bahcall, we estimate that only about one atom of Ar is produced
in the Davis Cl tank, but that about 50 electron recoils, with
energies of about 10 MeV, are produced in the Kamiokande II water
detector. We also estimate about 3 events each in the scintillators of
the University of Pennsylvania (Homestake Mine) and the Italian-
Russian collaboration (Mont Blanc). The results are sensitive to
the effective temperature of the emitted neutrino spectrum."
P. Murdin, Royal Greenwich Observatory, reports: "It is not
clear whether the relative constancy of the light curve of SN
1987A from Feb. 25 to Mar. 3 represents the maximum in a typical
type II light curve or the 20 day premaximum halt seen in SN 1940B
and 1941A. If SN 1987A follows precedent, either it will decline
soon to mag 6, where it will remain in the post-maximum plateau
until early May, or it will brighten in mid-March to a maximum at
mag about 2, remaining brighter than mag 6 until early July. Observers
should be aware of this uncertainty when planning observations."
Visual magnitude estimate by T. Beresford, Adelaide, South
Australia: Mar. 3.42 UT, 4.3.
1987 March 3 (4329) Brian G. Marsden
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