Electronic Telegram No. 4262
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


(2535) H{\"A}MEENLINNA
     V. Benishek, Belgrade Astronomical Observatory; D. Pray, Sugarloaf
Mountain Observatory, South Deerfield, MA, U.S.A.; P. Pravec, P. Kusnirak,
K. Hornoch, H. Kucakova, and J. Vrastil, Ondrejov Observatory; J. Pollock,
Appalachian State University; R. Groom and K. Stranger, Perth Observatory;
A. Carbognani, Astronomical Observatory of the Aosta Valley Autonomous
Region, Italy; R. Montaigut and A. Leroy, OPERA Observatory, France; and D.
Reichart and J. Haislip, University of North Carolina, Chapel Hill, report
that photometric observations taken with a 0.35-m telescope at the Sopot
Observatory in Serbia, a 0.50-m telescope at the Sugarloaf Mountain
Observatory, a 0.65-m telescope at the Ondrejov Observatory, a 0.36-m
telescope at the Perth Observatory, a 0.81-m telescope at the Observatory
of the Aosta Valley Autonomous Region, and a 0.20-m telescope at the OPERA
Observatory during 2015 Dec. 18-2016 Feb. 19 reveal that minor planet (2535)
is a binary system with an orbital period of 21.23 +/- 0.01 hr.  The primary
shows a period of 3.23106 +/- 0.00006 hr and has a lightcurve amplitude of
0.10 mag at solar phases 2-8 degrees, suggesting a nearly spheroidal shape.
Mutual eclipse/occultation events that are 0.05- to 0.10-magnitude deep
indicate a lower limit on the secondary-to-primary mean-diameter ratio of
0.22.  The secondary is synchronous, and it has an amplitude of 0.03 mag in
the observed lightcurve, suggesting a secondary elongation of about 1.5
after removing contribution of light from the primary.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2016 CBAT
2016 February 25                 (CBET 4262)              Daniel W. E. Green