Central Bureau for Astronomical Telegrams
IAUC 4347: 1987A
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Circular No. 4347
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. C. B. Ashley and S. M. Straw, Mt. Stromlo and Siding Spring
Observatories, telex: "We report 1- to 5-microns spectroscopic
observations of SN 1987A taken with the cooled infrared grating
spectrometer (resolving power 400) on the 2.3-m telescope on each of four
nights during the period Mar. 5-8; no changes were observed during
this time period. The continuum flux densities for for the JHKLM
bands are: J, 85 Jy; H, 70; K, 60; L, 35; M, 25. The following
H I lines were detected: 6-3, 5-3, 14-4, 12-4, 11-4, 10-4, 7-4,
8-5, 5-4. For each line that showed a P-Cyg profile, we measured
the velocity difference between the rest wavelength and the trough,
with the following results: 6600 km/s (6-3), 6400 (5-3), 5200 (10-
4), 5300 (7-4), 5000 (8-5), 6400 (5-4). The absorption trough of
H I (5-3) has a well-defined blueward edge which meets the continuum
at a velocity of 11800 km/s. Also, narrow emission lines are
seen at 1.575, 1.601, 1.620, 1.665, and 2.106 microns. The line
strengths are all roughly 3 x 10E-11 erg/cm**2/s. We tentatively identify
the first line as Fe II, and the remaining lines as [Fe II]."
V. Naumov, A. Vidmatchenko, and R. Zalles, Bolivian-Soviet
Astronomical Observatory, Tarija, report: "Spectra of SN 1987A
obtained on Mar. 6, 7, 8, 11, and 12 with the Zeiss 0.6-m reflector
(range 374-640 nm, resolution 0.5 nm) show strong, broad (line
width 5500-8900 km/s) emission at 389, 404, 425, 457, 514, 528, and
581 nm. The emission at 514 and 528 nm was blended. Double-peaked
emission was observed at 490 nm, like H-beta emission in Be stars. New
emission began on Mar. 7.04 UT at 418, 552, 564, and 611 nm. On
Mar. 12.08, V = 3.8 (comparison star delta Dor)."
A. V. Filippenko, University of California at Berkeley, notes:
"Atmospheric dispersion (e.g., Filippenko 1982, PASP, 94, 715) can
probably account for much of the blue enhancement in the 'northern
limb' of SN 1987A reported by Sun (IAUC 4343). At a zenith angle
of about 40 deg, when SN 1987A is on the meridian as viewed from CTIO, the
image blueward of 350 nm is displaced to the north from that at
visual wavelengths by at least 1". Some of the blue light, of
course, may be from star 2, about 3" northwest of Sanduleak -69 202.
Also, note that the feature at 372.7 nm reported in IAUC 4343 is
likely to be diffuse [O II] (IAUC 4341)."
Further visual magnitude estimates: Mar. 15.44 UT, 4.0 (D.
Seargent, The Entrance, N.S.W.); 16.42, 4.0 (Seargent); 17.40, 4.4
(G. Garradd, Tamworth, N.S.W.); 17.49, 4.1 (Seargent).
1987 March 18 (4347) Daniel W. E. Green
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