Central Bureau for Astronomical Telegrams
IAUC 4361: 1987A; 1987c
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Circular No. 4361
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
J. A. de Freitas Pacheco, Department of Astronomy, University
of Sao Paulo, reports: "We have obtained several spectra of SN
1987A at the National Laboratory for Astrophysics using a SIT-vidicon
(resolution about 0.7 nm). Our preliminary analysis shows that the
velocity of the blueshifted absorption minimum of the Balmer-line
P-Cyg profiles has been decreasing, as indicated by the following
H-alpha measures: Feb. 27.133 UT, -16 600 km/s; 28.029, -15 600; Mar.
1.048, -12 400; 6.950, -11 650; 11.934, -10 190; 12.914, -9580.
The other Balmer lines have the same behavior, but with the amplitude
of the velocity being smaller as the energy of the upper level
increases, in agreement with Danziger (IAUC 4326)."
A. M. Magalhaes and E. W. Velloso, Institute of Astronomy and
Geophysics, University of Sao Paulo, communicate: "We have been
monitoring SN 1987A with optical polarimeters at USP and at the
2.15-m reflector of the Complejo Astronomico, El Leoncito, and find
an intrinsically polarized component in the SN's light, as
evidenced by the variability and wavelength dependence of degree of
linear polarization and of its position angle. The degree of linear
polarization as observed through an H-alpha (3.6-nm bandpass) filter
was significantly distinct compared to R-filter measurements (
polarization is given as percentage; O is position angle, in degrees;
errors are given parenthetically in units of last figure quoted):
1987 UT H-alpha O(H-alpha) R O(R)
Mar. 21.125 0.83 (6) 38 (2) 0.48 (3) 38 (2)
22.135 0.81 (5) 40 (2) 0.47 (2) 39 (1)
25.119 0.75 (2) 40 (1) 0.44 (2) 41 (1)
26.087 0.76 (2) 40 (1) 0.42 (2) 41 (1)
27.072 0.73 (2) 37 (1) 0.41 (2) 37 (1)
This indicates that resonant scattering may be present in the SN's
atmosphere. Higher-resolution spectropolarimetry is encouraged."
Visual magnitude estimates by R. H. McNaught, Siding Spring
Observatory: Apr. 6.64 UT, 3.5; 7.48, 3.6.
COMET NISHIKAWA-TAKAMIZAWA-TAGO (1987c)
Total visual magnitude estimates: Mar. 27.79 UT, 6.7 (D. A. J.
Seargent, The Entrance, N.S.W., 15x80 binoculars); 30.33, 6.9 (V.
F. de Assis Neto, Sao Francisco de Oliveira, Brazil, 10x70 binoc.).
1987 April 8 (4361) Daniel W. E. Green
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