The CFHT "Image of the Week" celebrates its first anniversary this
week. One of the first discoveries we reported on these pages was the
little satellite associated to asteroid (45)
Eugenia. This week we present another spectacular image of an
asteroid, (216) Kleopatra. They show the shape of the Kleopatra as it
rotates! These images were obtained in the course of a two-year study of over
200 asteroids conducted with the Canada-France-Hawaii Telescope.
The results, presented last week at the 32nd Annual meeting of the
Division for Planetary Science of the American Astronomical Society in
Pasadena, show the elongated shape of Kleopatra. The rotation period
of the Asteroid is only about 6 hours so it was observed repeatedly
during one night of November 1999. A fixed view of the
results reveal the "dog-bone" shape of the asteroid. The numbers on
eqch of the frames is the rotation phase. Phase 0.0 is the beginning
of the rotation period while the frame at phase 0.5 was obtained half
a rotation later. Worthy of mention, the asteroid looks very similar
at phase 0.0 and 0.5.
Earlier this year, Steve Ostro of JPL published
reconstructions of Kleopatra's shape based on radar reflections
obtained when that asteroid was fairly close to the Earth, also in
November 1999, only a few days apart from the observations presented
here.
The excellent agreement of both optical and radar pictures of
Kleopatra's 'dog-bone' shape provides added confidence in the
reliability of adaptive optics images.
The adaptive optics images of Kleopatra covering a seven-hour period
were obtained with the CFHT equipped with PUEO, it's adaptive optics
instrument. A filter centered at 1.6 microns (H-Band) was used in the
KIR camera.
Kleopatra measures about 217 kilometers (135 miles) long and about 94
kilometers (58 miles) wide, and was at around 170 million kilometers
from Earth at the time of observation...
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