Electronic Telegram No. 4345
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
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Prepared using the Tamkin Foundation Computer Network


(12326) SHIRASAKI
     D. Pray, Sugarloaf Mountain Observatory, South Deerfield, MA, U.S.A.;
P. Pravec, Ondrejov Observatory; V. Benishek, Belgrade Astronomical
Observatory; J. Oey, Blue Mountains Observatory, Leura, NSW, Australia;
and V. Chiorny, Kharkiv Observatory, report that photometric observations
taken with a 0.50-m telescope at the Sugarloaf Mountain Observatory, a
0.35-m telescope at the Sopot Observatory in Serbia, a 0.35-m telescope at
the Blue Mountains Observatory, and a 0.70-m telescope at the Chuguev
station of the Kharkiv Observatory in Ukraine during 2016 Nov. 5-Dec. 6
reveal that minor planet (12326) is a binary system with an orbital period
of 25.06 +/- 0.02 hr.  The primary shows a period of 2.7286 +/- 0.0001 hr
and has a lightcurve amplitude of 0.12 mag at solar phases 5-7 degrees,
suggesting a nearly spheroidal shape.  Mutual eclipse/occultation events
that are 0.06- to 0.12-magnitude deep indicate a lower limit on the
secondary-to-primary mean-diameter ratio of 0.24.  Superimposed to the
primary and the eclipse/occultation lightcurves is a second rotational
lightcurve with a period of 12.7 +/- 0.1 hr, derived assuming two pairs
of maxima/minima per period, and an observed lightcurve amplitude of
0.03-0.04 mag.  It remains to be seen from future studies whether the
second rotational lightcurve belongs to the eclipsing/occulting secondary
or a possible third body in the system.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2017 CBAT
2017 January 12                  (CBET 4345)              Daniel W. E. Green