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Circular No. 6448 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Postal Address: Central Bureau for Astronomical Telegrams Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science) Phone 617-495-7244/7440/7444 (for emergency use only) COMET 1996 P2 R. H. McNaught, Anglo-Australian Observatory, reports the discovery by Kenneth S. Russell of a new comet on U.K. Schmidt plates taken by Fred G. Watson. The comet has a strong condensation (m2 about 17) within a 20" coma, and a 20' tail in p.a. 240 deg. The following positions were measured by McNaught: 1996 UT R.A. (2000) Decl. m1 Aug. 10.74014 1 40 24.85 -29 51 58.8 10.80264 1 40 25.78 -29 52 32.6 11.75125 1 40 39.80 -30 02 11.9 13 11.79292 1 40 40.36 -30 02 35.5 COMET C/1995 O1 (HALE-BOPP) R. W. Russell and D. Lynch, The Aerospace Corporation; M. Hanner, Jet Propulsion Laboratory; and M. Sitko, University of Cincinnati, report observations of C/1995 O1 on July 22.3 UT with the Infrared Telescope Facility and the Aerospace infrared spectrograph between 3 and 13.5 microns. The 8- to 13.5-micron spectrum showed a strong silicate emission feature (70 percent above the continuum), similar to those seen in comets 1P/Halley, C/1987 P1 (Bradfield), and C/1990 K1 (Levy). After division by a blackbody at the continuum temperature, the feature was trapezoidal with a roughly-flat top from about 9.9 to 11.5 microns and showed no significant additional spectral structure. The dust-continuum color temperature (from fitting a gray body to the 8- and 13-micron regions) was 200 +/- 10 K, or roughly 50 K warmer than the expected radiative equilibrium temperature of 145 K for a blackbody at 3.7 AU from the sun. Due to the cold continuum shape, no detection of the comet was made in the 3- to 5-micron region. Brightnesses of the comet in the 3".4-diameter beam at 8.0, 10.2, and 13.0 microns were 2, 6, and 5 x 10E-18 W cmE-2 micronE-1 (magnitudes 5.4, 3.2, and 2.4, respectively). COMET C/1996 N1 (BREWINGTON) Total visual magnitude estimates (cf. IAUC 6435): July 27.27 UT, 8.8 (C. E. Spratt, Victoria, BC, 0.20-m reflector); Aug. 4.90, 8.6 (R. J. Bouma, Groningen, The Netherlands, 0.25-m reflector); 7.24, 8.2 (Spratt); 9.24, 7.9 (Spratt); 10.93, 7.8 (B. H. Granslo, Fjellhamar, Norway, 0.20-m reflector); 11.24, 7.8 (Spratt); 11.90, 7.6 (Bouma, 15x80 binoculars). (C) Copyright 1996 CBAT 1996 August 12 (6448) Daniel W. E. Green
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