Electronic Telegram No. 5037
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
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(143649) 2003 QQ_47
     P. Pravec, P. Kusnirak, K. Hornoch, and P. Fatka, Ondrejov Observatory,
C. Snodgrass, University of Edinburgh; T. Hinse, Nicolaus Copernicus
University, Torun, Poland, and Chungnam National University, Daejeon, South
Korea; J. Tregloan-Reed, Universidad de Atacama; M. Devogele, Arecibo
Observatory and University of Central Florida; and N. Moskovitz, Lowell
Observatory, report that photometric observations taken with a 1.54-m
telescope at the La Silla station of the European Southern Observatory during
Aug. 29-Sept. 13 reveal that the Apollo-type minor planet (143649) is a
binary system with an orbital period of 13.065 +/- 0.018 hr.  The primary has
a period of 2.6446 +/- 0.0007 hr and a lightcurve amplitude of 0.07 magnitude
at solar phases 51-59 degrees, suggesting a nearly spheroidal shape.  Mutual
eclipse/occultation events that are 0.11 magnitude deep indicate a secondary-
to-primary mean-diameter ratio of 0.33 +/- 0.02.  The secondary appears
synchronous and has a light-curve amplitude (in the combined primary-plus-
secondary light curve) of 0.08 mag, suggesting a moderately elongated shape
with an equatorial-axis ratio of 1.4 +/- 0.2.  The system's mean absolute
magnitude is H = 17.66 +/- 0.32, assuming a phase-relation slope parameter
G = 0.33 +/- 0.20.  The color index in the Johnson-Cousins photometric system
is (V - R) = 0.426 +/- 0.010.  Spectroscopic observations taken with the
DeVeny spectrograph at the 4.3-m Lowell Discovery Telescope in the wavelength
range 0.38-1.0 micron reveal it to be of Sq-type in the Bus-DeMeo taxonomic
system.  These observations were taken in the framework of their NEOROCKS,
MiNDSTEp and MANOS projects.  Follow-up observations are encouraged.


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2021 September 17                (CBET 5037)              Daniel W. E. Green