Central Bureau for Astronomical Telegrams
IAUC 4320: 1987A
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Circular No. 4320
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
M. W. Feast, South African Astronomical Observatory, reports
the following provisional photometry by H. Winkler: Feb. 24.8 UT,
V = 4.63, B-V = +0.11, U-B = -0.79, V-R = +0.26, V-I = +0.34;
25.9, V = 4.52, B-V = +0.23, U-B = -0.52, V-R = +0.30, V-I =
+0.40. He also reports infrared photometry by R. Catchpole on
Feb. 25.8 UT: J = 3.81, H = 3.68, K = 3.46, L = 3.17.
P. Andreani and A. Vidal-Madjar, Institut d'Astrophysique,
Paris, currently observing at the European Southern Observatory,
report the detection (using the CAT+CES+reticon at resolving power
10**5) of interstellar/intergalactic components in the direction of
the supernova. The Ca II H and K lines show more than 22
components, Na I D1 and D2 show more than 13. The observed features
are all spread within a velocity range of 270 +/- 5 km/s. At least
two absorption features were detected for K I 768 nm, but
preliminary analysis shows nothing near Ca I 423 nm.
J. Dachs, University of Bochum, telexes that he has been
obtaining flux-calibrated spectrograms (1 nm bandpass) of SN 1987A
between 320 and 870 nm using a photoelectric rapid-mode spectrum
scanner attached to the 0.61-m Bochum reflector at the European
Southern Observatory. Very strong, broad P-Cyg-type emission
lines are found to peak near 643 (H alpha), 580, 480 (H beta) and 428 nm
(H gamma), increasing in strength during Feb. 25.0-26.1 and suggesting
a type II supernova spectrum. P Cyg absorption cores are shifted
by about 17 000 km/s at H alpha, -14 500 km/s at H beta and -13 000 km/s at
H gamma. A strong ultraviolet continuum in the 320-370-nm wavelength region
decreased in intensity over the same time.
G. Sonneborn, Goddard Space Flight Center; and R. Kirshner,
Center for Astrophysics, report the following fine-error-sensor
(i.e., about mpg) magnitudes measured with IUE: Feb. 24.82 UT, 4.53 +/-
0.02; 25.00, 4.49; 25.82, 4.45; 25.96, 4.40; 26.46, 4.41; 26.63,
4.41. In contrast to the steady flux at those wavelengths, the
short-wavelength ultraviolet flux has begun to decline rapidly.
At 186 nm the flux declined from 8.5 x 10**-11 erg cm-1 s-1 A-1 on
Feb. 24.98 UT to 4.2 x 10**-11 on Feb. 25.85. At 160 nm the
decrease was a factor of 7 and at 140 nm a factor of 13.
Observations at both high and low dispersions with both the long and
short wavelength cameras continue.
Visual magnitude estimates by R. H. McNaught, Coonabarabran,
N.S.W.: Feb. 26.401 UT, 4.4; 26.512, 4.1; 26.646, 4.1; 26.749, 4.0.
1987 February 26 (4320) Brian G. Marsden
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