Electronic Telegram No. 2766
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; 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


(2691) SERSIC
     J. Oey, Leura, N.S.W., Australia; P. Pravec and P. Kusnirak, Ondrejov
Observatory; N. Morales and A. Thirouin, Instituto de Astrofisica de Andalucia;
J. Pollock, Appalachian State University; and D. E. Reichart, K. M. Ivarsen,
J. B. Haislip, and A. LaCluyze, Physics and Astronomy Department, University
of North Carolina, Chapel Hill, report that photometric observations taken
during 2011 June 3-July 7 reveal that minor planet (2691) is a binary system
with an orbital period of 26.81 +/- 0.01 hr.  The primary light-curve
component shows a period of 3.8811 +/- 0.0003 hr and it has an amplitude of
0.21 mag.  Observed mutual eclipse/occultation events were up to 0.45-mag
deep.  From a depth of the secondary event, they estimate a lower limit on
the secondary-to-primary mean-diameter ratio of 0.43 +/- 0.02.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2011 CBAT
2011 July 16                     (CBET 2766)              Daniel W. E. Green