[IAUC] CBET 964: 20070516 : (121) HERMIONE

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                                                  Electronic Telegram No. 964
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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CBAT en CFA.HARVARD.EDU (science)
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(121) HERMIONE
     P. Descamps, Institut de Mecanique Celeste et de Calcul des Ephemerides
(IMCCE), Paris; F. Marchis, University of California at Berkeley; J. Pollock,
Appalachian State University; J. Berthier and F. Vachier, Institut de
Mecanique Celeste et de Calcul des Ephemerides, Paris; T. Michalowski, Adam
Mickiewicz University; and J.-P. Teng, A. Peyrot, and C. Benard, Les Makes
Observatory, Reunion Island, report that a photometric observation program
initiated in March 2007 of the minor planet (121) Hermione confirms the
bilobated shape of the primary suggested by direct Keck adaptive-optics
imaging taken in 2003 (IAUC 8264; Marchis et al. 2005, Icarus 178, 450).
According to the orbital model of the satellite companion (cf. IAUC 7980),
the system is currently viewed edge-on.  The lightcurves recorded mostly at
the Make Observatory (Reunion Island) over seven nights reveal the high
amplitude of the brightness variation (up to 0.75), with a morphology
typical of a contact binary composed of two unequal components with a size
ratio of about 0.6.  Follow-up photometric observations that will help to
refine and improve the shape and pole solution of Hermione (currently V
about 12.6) are encouraged.  The current amplitude is about 0.6 mag, but
this should quickly decrease, as the equatorial plane will open to the
line-of-sight.


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                         (C) Copyright 2007 CBAT
2007 May 16                      (CBET 964)               Daniel W. E. Green