Central Bureau for Astronomical Telegrams
IAUC 4337: 1987A; 1986l
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Circular No. 4337
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 1987A IN THE LARGE MAGELLANIC CLOUD
P. Barrett, University of Cape Town, provides broadband
polarization measurements, made with the U.C.T. photometer and 'Stokes'
polarimeter module on the 1.0-m telescope at the Sutherland station
of the South African Astronomical Observatory:
U B V R I
A P 0.92 (22) 0.92 (18) 0.964 (94) 0.855 (14) 0.682 (36)
O 39 (19) 26 (16) 39.8 (79) 39.4 (14) 36.3 (43)
V -0.46 (15) -0.04 (13) -0.076 (66) +0.030 (10) +0.062 (25)
B P 0.58 (11) 0.92 (10) 0.848 (88) 0.786 (76) 0.642(104)
O 29 (15) 38 (9) 34.8 (85) 38.2 (79) 41.2 (131)
V +0.01 (7) -0.07 (7) +0.17 (63) +0.032 (54) +0.042 (73)
The polarizations P (in percent) are at position angle O (deg),
and V is the circular polarization (in percent). The errors (in
parentheses) are in units of the last figure quoted. Observations
A were made on Feb. 28, B on Mar. 2 (except that the V-band
observations were on Mar. 1). The corresponding V-band observations
for a comparison star of mag 10.3 are P = 0.966 (140), O = 35.9
(117), V = -0.065 (99). The polarization does not appear to be
intrinsic (although the use of more comparison stars is needed to
verify this) but due to the interstellar medium.
S. Ryan, Mt. Stromlo Observatory, reports: "Spectra (range
320-740 nm) were obtained on Mar. 6.5, 7.4 and 8.4 UT. Since Mar.
3.5 (IAUC 4331) absorption features have continued to strengthen
and move redward by about 1 nm/day. The 504.5 (Mg 'B' 517?) and 575-nm
(He I 587.6?) absorptions have changed from residual intensities of
90 percent of continuum to 60 percent in three days. In addition,
numerous new broad absorption features have appeared, in particular
a strong feature in the blue edge of the HG P Cyg absorption."
COMET WILSON (1986l)
Total visual magnitude estimates: Feb. 28.4 UT, 8.1 (I.
Ferrin, Merida, Venezuela, 20 x 120 bin.); 28.77, 7.5 (G. Garradd,
Tamworth, N.S.W., 7 x 50 bin.); Mar. 1.10, 7.2 (J. Campos, Durban,
R.S.A., 0.13-m refr.); 1.4, 7.9 (Ferrin); 4.52, 7.9: (A. Hale, Las
Cruces, NM, 0.20-m refl.); 6.77, 7.4 (Garradd, 0.15-m refl.); 7.52,
7.9 (Hale); 7.77, 7.2 (Garradd, 0.15-m refl.); 8.75, 7.2 (Garradd,
7 x 50 bin.). Garradd noted a 7' tail in p.a. 5 deg on Mar. 7.
1987 March 9 (4337) Brian G. Marsden
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