Despite many decades of minor planet studies focused
on external and dynamical properties, there are still
hundreds of asteroids that have never been measured.
Presented here are the results of photometric analysis
applied to five main-belt asteroids. In addition to
calculating rotation period, axis ratios assuming a simple
ellipsoidal shape and the estimated minimum density of
each asteroid are reported.
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 Â± 0.4 hr. The primary shows a period of 2.9661 Â±
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.