Electronic Telegram No. 507 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) CBAT@CFA.HARVARD.EDU (science) URL http://cfa-www.harvard.edu/iau/cbat.html (4029) BRIDGES D. Higgins, Canberra, Australia; P. Pravec and P. Kusnirak, Ondrejov Observatory; W. Cooney, J. Gross, and D. Terrell, Sonoita Research Observatory, Sonoita, AZ; and R. Stephens, Yucca Valley, CA, report that photometric observations obtained during Apr. 11-May 4 reveal that minor planet (4029) is a binary system with an orbital period of 16.31 +/- 0.01 hours. The primary rotates with a period of 3.5746 +/- 0.0001 hours, and it has a lightcurve amplitude of 0.20 mag. Mutual eclipse/occultation events that are 0.06-0.12 mag deep indicate a secondary-to-primary mean-diameter ratio of 0.24 +/- 0.02. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2006 CBAT 2006 May 8 (CBET 507) Daniel W. E. Green