Electronic Telegram No. 2427
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Room 209; Dept. of Earth and Planetary
 Sciences; Harvard University; 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbat@iau.org; cbatiau@eps.harvard.edu
URL http://www.cfa.harvard.edu/iau/cbat.html


(2121) SEVASTOPOL
     D. Higgins, Canberra, Australia; P. Pravec and P. Kusnirak, Ondrejov
Observatory; J. Pollock, Appalachian State University; J. Oey, Leura, N.S.W.,
Australia; M. Husarik and G. Cervak, Skalnate Pleso Observatory; 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 obtained during July 23-Aug. 24 reveal that minor planet (2121)
is a binary system with an orbital period of 37.1 hr.  The primary shows a
period of 2.90640 +/- 0.00002 hr, and it has a lightcurve amplitude of 0.20
mag.  Mutual eclipse/occultation events that are 0.2-mag deep indicate a
secondary-to-primary mean-diameter ratio of 0.41 +/- 0.02.  The secondary
rotates synchronously with the orbital motion and shows an amplitude of 0.06
mag in the combined lightcurve of the system.  Due to the high solar phase,
the observed eclipse/occultation events also describe the satellite-shadow
transit and satellite's passage through the parent body's shadow.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2010 CBAT
2010 August 26                   (CBET 2427)              Daniel W. E. Green