Circular No. 4196 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 PERIODIC COMET HALLEY (1982i) M. Feast, South African Astronomical Observatory, telexes the following infrared magnitudes of P/Halley obtained by B. Carter with the 0.75-m reflector at Sutherland (36"-aperture diaphragm, 170" chop): Mar. 15.1 UT, J = 4.95, H = 4.54, K = 4.30, L = 2.08; 17.1, 5.50, 5.08, 4.87, 2.79; 18.1, 5.46, 5.04, 4.83, 2.85. A. Tokunaga, W. Golisch, and L. Bergknut, University of Hawaii, communicate infrared observations made of P/Halley with the NASA Infrared Telescope Facility (magnitudes obtained with 7"3 aperture; errors < 0.05 mag): Mar. 6.9 UT, K = 6.3, L = 3.6, M = 1.3, N = -2.5, Q = -3.9; Mar. 12.8, 6.4, 4.2, 2.1, -2.0, -3.6; Mar. 13.7, 7.0, 4.7, 2.3, -1.8, --. The color temperature of the dust emission was 370 K on Mar. 6 and 345 K on Mar. 12; the silicate emission at 9.8 microns was ~ 0.6 mag above the continuum. R. M. West reports the following information from photographs taken (mostly with the 0.4-m astrograph) at the European Southern Observatory, La Silla: On Mar. 1.4, the nucleus was 2" or less in size and round; exposures of 20 and 60 s show a segment emanating from the nucleus at p.a. 0 and curving toward p.a. 270. On Mar. 2.4, the nucleus appeared much brighter, 2" across, and at the west edge of a bright segment, indicating an outburst had occurred in the preceding 24 hr. On Mar. 3.4, the nucleus was again somewhat fainter than the preceding day; the total intensity of the first degree of tail length outward from the nucleus had decreased somewhat over the previous 3 days, especially in red. On Mar. 4.4, a very noticeable decrease in 24 hr in the red brightness of the nucleus (~ 0.5 mag or more) and of the surrounding matter was visible; however, there were more streamers in the tail within 1 deg of the nucleus on blue exposures. On Mar. 5.4 and 6.4, the nucleus was somewhat brighter than on Mar. 4.4. On Mar. 7.3, a major outburst was recorded, with the nucleus being about 1 mag brighter than on Mar. 6.3 and elongated on even the shortest exposures. P. Bouchet, F. Dossin, and P. Monderen report observation of a clear secondary condensation, anti-solar from the main condensation, on Mar. 19.3 with the La Silla 2.2-m and 1.5-m reflectors and 0.4-m astrograph. Further total visual magnitude estimates (cf. IAUC 4194): Mar. 13.10 UT, 3.0 (J. Campos, Durban, South Africa, naked eye; tail 5 deg long in p.a. ~ 275 ); 17.52, 2.8 (C. S. Morris, Little Rock, CA, naked eye); 20.52, 2.8 (Morris, tail length ~ 10 deg). 1986 March 20 (4196) Daniel W. E. Green
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