Electronic Telegram No. 5634
Central Bureau for Astronomical Telegrams
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(849935) 2006 RA_55
     P. Pravec, P. Kusnirak, K. Hornoch, P. Fatka, H. Kucakova, and A. Galad,
Ondrejov Observatory; and K. Ergashev and O. Burkhonov, Ulugh Beg Astronomical
Institute, Tashkent, Uzbekistan, report that photometric observations taken
with a 1.54-m telescope at the La Silla station of the European Southern
Observatory and a 1.5-m telescope at Maidanak Observatory in Uzbekistan during
Oct. 13-27 reveal that the Amor-type minor planet (849935) is a binary system
with an orbital period of 9.728 +/- 0.005 hr.  The primary has a period of
2.5218 +/- 0.0003 hr and a lightcurve amplitude of 0.06 magnitude at solar
phases 1-7 degrees, suggesting a nearly spheroidal shape.  Mutual eclipse/
occultation events that are 0.08 magnitude deep indicate a secondary-to-
primary mean-diameter ratio of 0.28 +/- 0.02.  The system's mean absolute
magnitude is H = 19.65 +/- 0.03 with a phase-relation slope parameter G =
0.30 +/- 0.03.  The color index in the Johnson-Cousins photometric system is
(V - R) = +0.39 +/- 0.02.  These observations were taken in the framework of
their NEOSource project, supported by the "Praemium Academiae" award from the
Academy of Sciences of the Czech Republic.  Follow-up observations taken
during the rest of the current apparition of the minor planet are encouraged,
to improve the characterization of the binary system.


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2025 November 6                  (CBET 5634)              Daniel W. E. Green