[IAUC] CBET 836: 20070207 : (617) PATROCLUS

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                                                  Electronic Telegram No. 836
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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(617) PATROCLUS
     F. Marchis and M. Baek, University of California at Berkeley; and
J. Berthier, P. Descamps, D. Hestroffer, and F. Vachier, Institut de
Mecanique Celeste et de Calcul des Ephemerides (IMCCE), Paris Observatory,
report on the observations of (617) Patroclus and its companion Menoetius
(cf. IAUC 7741, 8666) with the recently available Laser Guide Star system
and its adaptive-optics system at the Gemini North observatory on Jan.
13.625 UT.  Both components are visible, with Menoetius separated from
Patroclus by 0".10 in p.a. 178 deg.  The geometry of the system was in
rough agreement with the one predicted from the orbital model published
one year ago (Marchis et al. 2006, Nature 439, 565), confirming that the
binary system is in occultation/eclipse configuration during Feb.-July
2007.  Based on that prediction, two mutual events were observed
successfully by F. Colas (IMCCE) and J. Lecacheux (LESIA, Paris
Observatory), with contributions by V. Reddy (University of North Dakota)
and F. Pino (Ironwood North Observatory, Mesa, AZ) starting on Jan. 27.008
and 29.04 for about 5.5 hr using the 1-m Pic du Midi telescope and the
0.25-m Ironwood North telescope.  The lightcurve has a drop in brightness
of about 0.2 magnitude and clearly shows the signature of the occultation
followed by an eclipse.  The timing of the events can be found at
http://www.imcce.fr/page.php?nav=en/observateur/campagnes_obs/patroclus/.
Additional observations are encouraged to refine the size, shape,
surface composition, and orbital parameters of the system components.


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                         (C) Copyright 2007 CBAT
2007 February 7                  (CBET 836)               Daniel W. E. Green