CFHT, Current Image of the Week


November 6th, 2000

Kleopatra, the Flying Dog-Bone!

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Kleopatra, the Flying Dog-Bone!

Credit: Image courtesy of B.Merline1, C.Dumas2 & F.Ménard3

1 Southwest Reasearch Institute, Boulder, Colorado
2 JPL / Caltech, Pasadena, California
3 CFHT, Hawaii

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.

Technical description:

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...

next week: To be announced shortly

editors: François Ménard, Jean-Charles Cuillandre, & Catherine Dougados
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CFHT is funded by the Governments of Canada and France, and by the University of Hawaii.