Electronic Telegram No. 2583 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network (596) SCHEILA S. Larson, Lunar and Planetary Laboratory (LPL), University of Arizona, reports that images of the main-belt minor planet (596), taken on Dec. 11.44- 11.47 UT with the 0.68-m f/1.8 Schmidt telescope at Catalina, show the object to be in apparent outburst with a comet-like appearance, showing a total V magnitude of about 13.4 and an envelope that extends 2' north and 5' west of the central condensation. The cometary appearance has been confirmed by other observers, including R. Kowalski with the Mt. Lemmon 1.5-m f/2 reflector on Dec. 11.54; H. Sato (Tokyo, Japan) remotely with a 0.25-m f/3.4 reflector at the RAS Observatory near Mayhill, NM, U.S.A., on Dec. 11.5 (noting a wide and diffuse tail 1'.5 long in p.a. 280 degrees, with a spike-like tail 45" long toward p.a. 225 degrees); and K. Yoshimoto (Hirao, Yamaguchi, Japan; forwarded by S. Nakano, Sumoto), whose unfiltered CCD image on Dec. 11 taken with a 0.16-m f/6.3 reflector shows a coma diameter of 1'.3 and a tail 1' long in p.a. 250 deg. Alex Gibbs, LPL, has looked at recent Catalina images of (596) taken on 2010 Oct. 18, Nov. 2, Nov. 11, and Dec. 3; he notes that the object appears essentially stellar in appearance on the first three dates (with the object's V magnitude in November being around 14.5 on sets of four co-added 30-s exposures), but that on Dec. 3.4 it shows some slight diffuseness with V magnitude 13.2 on four 45-s co-added exposures. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 December 12 (CBET 2583) Daniel W. E. Green