Electronic Telegram No. 5287
Central Bureau for Astronomical Telegrams
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(458732) 2011 MD_5
    P. Pravec, K. Hornoch, H. Kucakova, and P. Fatka, Ondrejov Observatory;
and K. Ergashev and O. Burkhonov, Ulugh Beg Astronomical Institute, Tashkent,
Uzbekistan, report that photometric observations taken with a 0.65-m telescope
at Ondrejov Observatory and a 1.5-m telescope at Maidanak Observatory in
Uzbekistan during Aug. 7-21 reveal that the Apollo-type minor planet (458732)
is a binary system with an orbital period of 15.16 +/- 0.02 hr.  The primary
has a period of 3.1350 +/- 0.0006 hr and a lightcurve amplitude of 0.15
magnitude at solar phases 20-23 degrees, suggesting a nearly spheroidal shape.
Mutual eclipse/occultation events that are 0.09 to 0.16 magnitude deep
indicate a secondary-to-primary mean-diameter ratio of 0.29 +/- 0.02.
Follow-up observations taken around the upcoming approach of the minor planet
to the earth in September are encouraged, as they should allow the
construction of a model of the binary system.


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                         (C) Copyright 2023 CBAT
2023 August 24                   (CBET 5287)              Daniel W. E. Green