Central Bureau for Astronomical Telegrams
IAUC 4367: 1987A
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Circular No. 4367
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
F. Giovannelli, Istituto di Astrofisica Spaziale, CNR,
Frascati and Instituto de Astrofisica de Canarias, La Laguna,
Tenerife; and V. G. Kurt and E. K. Sheffer, Space Research Institute,
U.S.S.R. Academy of Sciences, report: "The Soviet station
ASTRON has monitored SN 1987A from Mar. 4 to 17 in the energy
range 2-25 keV. Upper limits at the 3-sigma level have been found for
the emitted fluxes as follows: Mar. 4.71-4.75 UT, 12 mCrab; 6.78-
6.82, 7; 9.62-9.70, 14; 12.61-12.68, 5; 17.66-17.73, 9."
M. L. Hazen, Center for Astrophysics, writes: "No major change
in the brightness of Sk -69 202 was found in a search of the star's
area on 502 Harvard blue patrol plates taken 1899-1953 at a focal
scale of 600"/mm and on 59 plates of the Damon blue patrol series
taken in 1971, 1978-79, and 1981-86 at a focal scale of 580"/mm.
The light of Sk -69 202 was always blended with its nearby companions.
The data do suggest, however, that Sk -69 202 may have been
varying by +/- 0.3-0.5 mag over that interval."
J. Dachs and R. Hanuschik, University of Bochum, communicate:
"We have obtained continuous spectrophotometry (resolution 1 nm,
range 320-900 nm) and spectroscopy (0.3-nm resolution) of SN 1987A
since Feb. 25 with the Bochum 0.61-m reflector (with a rapid scanner;
cf. IAUC 4320) at La Silla, and find the following preliminary
results. Between Feb. 25.0 and Mar. 10 UT, the continuum flux at
wavelengths shorter than 550 nm rapidly faded, while it increased
above 700 nm; since Mar. 10, only minor continuum variations are
observed. Flux maximum was at about 450 nm on Feb. 25.0 and at 600 nm
on Mar. 25.2. Since Feb. 25.0 H-alpha is constantly visible as a P-Cyg-
type profile. H-beta and H-gamma temporarily showed emission components.
The feature near 588 nm (probably He I before and Na I after Mar.
2) was always visible except for the period Feb. 27-Mar. 2. The Ca
II triplet at 860 nm appeared on Feb. 27.0 and within 1 day became
a very prominent P-Cyg feature. At least 12 additional lines
developed in our spectral range since Mar. 4, all of them apparently
exhibiting P-Cyg features. Line profiles now tend to show fine
structure. Since Mar. 19, H-alpha exhibits, in addition to the blue
emission peak (cf. IAUC 4350), a further bump on the red wing at a
velocity of ~ +4000 km/s. The velocity of the H-alpha absorption minimum
was at -6300 km/s on Apr. 13.2, decreasing at a rate of only 50
km/s/day since Mar. 21. The maximal H-alpha velocity (blue edge) was
-31 000 km/s on Feb. 25; the H-alpha velocity is now at -10 000 km/s."
1987 April 15 (4367) Daniel W. E. Green
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