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: http://www.iki.rssi.ru/solar/eng/kuiper.htm
Дата изменения: Thu Oct 16 01:00:30 1997 Дата индексирования: Tue Oct 2 05:06:29 2012 Кодировка: Поисковые слова: lightning |
Kuiper belt objects are icy bodies in the outer solar system. They reside in a region past the orbit of Neptune. Pluto and Charon may be the largest examples of these objects. Several of these objects have been discovered during the last few years.
| Views of Kuiper Belt Objects |
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Object 1993 SC
This image shows a small part of the discovery frames of 1993 SC,
one of the brightest Kuiper-Belt objects so far discovered. It was
taken using the 2.5 meter Isaac Newton Telescope on La Palma by Alan
Fitzsimmons, Iwan Williams and Donal O'Ceallaigh on September 17, 1994.
The two images are separated in time by 4.6 hours, and by comparing
them it is clear that one of the objects has moved from upper left of
center to a point where its image almost merges with that of a distant
galaxy. This motion marks it as being a distant member of our solar
system, further away than the planet Neptune.
Subsequent observations over the past year confirm that it is currently
34.0 AU from the sun; however, with a moderate orbital eccentricity of
0.18 it might travel as far as 48 AU. Assuming that Object 1993 SC
reflects light much like other primitive asteroids and comets in the
out solar system, the diameter is around 300 kilometers (186 miles),
or just a quarter the size of Pluto's moon Charon.
Hubble Detection of Comet Nucleus
This pair of images shows one of the candidate Kuiper Belt objects
found with Hubble Space Telescope. The object is believed to be an
icy comet nucleus several miles across. Each photo is a 5-hour
exposure of a piece of sky carefully selected such that it is nearly
devoid of background stars and galaxies that could mask the elusive
comet.
The left image, taken on August 22, 1994, shows the candidate comet
object (inside circle) embedded in the background. The right picture,
taken of the same region one hour forty-five minutes later, shows the
object has apparently moved in the predicted direction and rate of
motion for a Kuiper Belt member. The dotted line on the images is a
possible orbit that this Kuiper Belt comet is following. A star (lower
right corner) and a galaxy (upper right corner) provide a static
background reference. In addition, other objects in the picture have
not moved during this time, indicating they are outside our solar
system.
(Credit: A. Cochran, University of Texas/NASA)
Comet
Shoemaker-Levy 9 Impact