Electronic Telegram No. 1046 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://www.cfa.harvard.edu/iau/cbat.html (160256) 2002 PD_149 K. S. Noll and S. D. Kern, Space Telescope Science Institute (STScI); W. M. Grundy, Lowell Observatory; D. C. Stephens, Brigham Young University; and H. F. Levison, Southwest Research Institute, report the detection of a binary companion to the transneptunian object (160256) 2002 PD_149 (MPEC 2002-S49; MPO 121459). The observations were made during May 22.195-22.212 UT with the Planetary Camera of the Wide Field Planetary Camera 2 on the Hubble Space Telescope, using the F606W filter (wide V) with one 260-s exposure at each of three dithered positions on the detector. The two components were separated by an angular distance of 0".74 +/- 0".01 and differ in brightness by 0.4 mag. The fainter component lies at a position angle of 62.0 +/- 0.8 deg from the primary. The projected separation of the objects in the sky plane is 24400 +/- 300 km. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2007 CBAT 2007 August 31 (CBET 1046) Daniel W. E. Green