[IAUC] CBET 1297: 20080312 : (3749) BALAM

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                                                  Electronic Telegram No. 1297
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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(3749) BALAM
     F. Marchis, Carl Sagan Center (CSC), SETI Institute; J. Pollock,
Appalachian State University (ASU); P. Pravec, Ondrejov Observatory; M. Baek,
CSC; J. Greene and L. Hutton, ASU; P. Descamps, Institut de Mecanique Celeste
et de Calcul des Ephemerides; and D. E. Reichart, K. M. Ivarsen, J. A. Crain,
M. C. Nysewander, A. P. Lacluyze, J. B. Haislip, and J. S. Harvey, University
of North Carolina at Chapel Hill, report that photometric observations
obtained during 2007 July 15 to Oct. 19 reveal that the central object of
(3749) is actually a binary system with a mutual orbital period of 33.38 +/-
0.02 hr.  The primary shows a rotation period of 2.80483 +/- 0.00002 hr and
a lightcurve amplitude of 0.13 mag.  Mutual eclipse/occultation events that
were 0.15 and 0.43-mag deep on July 18 and Sept. 8, respectively, indicate a
size ratio of the two inner components of 0.4 +/- 0.1.  The system's
parameters need to be refined with further observations.  A distant satellite
of (3749) was discovered in 2002 (see IAUC 7827) at a distance of 0."47 using
adaptive optics (AO) imaging capabilities.  A separation between the two
inner components showing mutual events is estimated to be roughly 20 km,
corresponding to an angular separation of about 0".02, not yet attainable
with current AO systems.


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                         (C) Copyright 2008 CBAT
2008 March 12                    (CBET 1297)              Daniel W. E. Green