Circular No. 4481 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 A. Chalabaev, Observatoire de Haute Provence; and C. Perrier and J. M. Mariotti, Observatoire de Lyon, telex: "Near-infrared speckle interferometry of SN 1987A at the European Southern Observatory 3.6-m telescope (cf. IAUC 4389, 4417) was continued on Aug. 6, yielding the detection of a weak modulation superimposed on the visibility function of the unresolved ejecta. The data were obtained using K, L, and M filters aligned north-south, and with the K filter aligned east-west. The modulation is present in all observations, which can be satisfied by one of three possibilities: (1) the unresolved ejecta and two infrared spots, one lying to the north (or south) and another to the east (or west) of the SN (both being 0".35 +/- 0".04 from the SN, and each contributing about 2.5 percent to the total flux); (2) combining the two spots into one spot lying at an intermediate direction; or (3) a ring of 0".41 +/- 0".08 diameter, contributing about 3 percent of the total flux. The velocity scale of the phenomenon is at least 0.4c, meaning that we are observing an infrared light echo. The analysis of the dust density necessary to account for the observed flux and the axial symmetry favors the ring as the most plausible explanation for these observations. The whole set of ESO speckle observations carried out from May to Aug. allows us to conclude that, during this time, the 2- to 5-micron flux was dominated by the unresolved ejecta which contributed at least 95 percent of the total flux in each infrared band, with the exception of the L band (where during June 16-21 the lower limit on the ejecta contribution may be set at about 80 percent). This implies that any suspected infrared 'excess' over 5 percent in K or M does not come from a light echo but from the ejecta, and/or the material within the ejecta, and/or the outer region immediately surrounding the ejecta." G. K. Moore and A. Deliseo, University of Wollongong, report the following photometry obtained on Oct. 27.58 UT: V = 5.65, B-V = +1.30, V-R = +1.06, V-I = +1.53. Corrigendum: on IAUC 4474, Supernova 1987A, line 1, for Wollonrong read Wollongong. Visual magnitude estimates: Oct. 22.49 UT, 5.8 (D. Seargent, The Entrance, N.S.W.); 24.42, 5.6 (A. C. Beresford, Adelaide, South Australia); 25.42, 5.5 (Beresford); 26.76, 5.6 (R. H. McNaught, Siding Spring Observatory); 27.53, 5.9 (Seargent); 28.44, 5.6 (Beresford); 29.45, 5.6 (Beresford); 30.47, 5.7 (Beresford). 1987 November 2 (4481) Daniel W. E. Green
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