Binary asteroid discovery IAU announcement

IAU CBET nº4321

(27675) 1981 CH
D. Pray, Sugarloaf Mountain Observatory, South Deerfield, MA, U.S.A.;
P. Pravec, H. Kucakova, K. Hornoch, P. Kusnirak and J. Vrastil, Ondrejov
Observatory; A. Carbognani, Astronomical Observatory of the Aosta Valley
Autonomous Region, Italy; A. Aznar, Isaac Aznar Observatory, Centro
Astronomico del Alto Turia, Aras de los Olmos, Spain; V. Benishek, Belgrade
Astronomical Observatory; W. Cooney and J. Gross, Sonoita Research
Observatory, Sonoita, AZ, U.S.A.; D. Terrell, Southwest Research Institute;
and R. Montaigut and A. Leroy, OPERA Observatory, France, report that
photometric observations taken with a 0.50-m telescope at the Sugarloaf
Mountain Observatory, a 0.65-m telescope at the Ondrejov Observatory, a
0.81-m telescope at the Observatory of the Aosta Valley Autonomous Region,
a 0.35-m telescope at the Isaac Aznar Observatory, a 0.35-m telescope at the
Sopot Observatory in Serbia, a 0.50-m telescope at the Sonoita Research
Observatory, and a 0.20-m telescope at the OPERA Observatory during 2016 Dec.
21-2017 Feb. 1 reveal that minor planet (27675) is a binary system with an
orbital period of 120.1 ± 0.4 hr. The primary shows a period of 2.9661 ±
0.0004 hr and has a lightcurve amplitude of 0.11 mag at solar phases 9-13
degrees, suggesting a nearly spheroidal shape. Mutual eclipse/occultation
events that are 0.04- to 0.06-magnitude deep indicate a lower limit on the
secondary-to-primary mean-diameter ratio of 0.20.