Electronic Telegram No. 279
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)
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(3309) BRORFELDE
    B. D. Warner, Palmer Divide Observatory, Colorado Springs; P.
Pravec and P. Kusnirak, Ondrejov Observatory; W. Cooney, J. Gross,
and D. Terrell, Sonoita Research Observatory, Sonoita, AZ; and S.
Nudds, Elginfield Observatory, University of Western Ontario,
report that photometric observations obtained from Oct. 25 to Nov.
3 show that the minor planet (3309) is a binary system with an
orbital period of 18.48 +/- 0.01 hr.  The primary rotates with a
period of 2.5041 +/- 0.0002 hr, and its lightcurve amplitude of 0.09
mag indicates a nearly spheroidal shape.  Mutual eclipse/occultations
events that are 0.07-0.15 mag deep indicate a secondary-to-primary
mean-diameter ratio of 0.26 +/- 0.02.  Calibrated data gives an
estimated absolute magnitude H_R = 13.4 +/- 0.2, assuming G = 0.15
+/- 0.2.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2005 CBAT
2005 November 7                  (CBET 279)               Daniel W. E. Green