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http://skyandtelescope.com/news/article_1394_1.asp]The universe is endlessly fascinating :up:
*Article regards contact binaries.
Among the strangest denizens of the solar system are contact binaries. In these systems, two minor planets orbit each other so closely that they literally or nearly touch end-to-end — resulting in a peanut-like overall shape. Until now, astronomers had found only two possible contact binaries of relatively large size: the main-belt asteroid 216 Kleopatra and the Trojan asteroid 624 Hektor. Now Scott S. Sheppard (Carnegie Institution of Washington) and David C. Jewitt (University of Hawaii) may have found a third example: a Kuiper-Belt object orbiting beyond Pluto.
*Geez...one of these objects is so far out even Hubble can't resolve a specific shape (yes, I realize this object is extremely small -- which certainly factors in). :-\ Magnitude varies by 1.14 every 6.89 hours. However, its color doesn't change "which suggests that dark spots rotating in and out of view are not causing the brightness changes."
With an average diameter of about 180 kilometers, 2001 QG298 is large enough that it should be nearly spherical. But the object is not spinning fast enough for rotation to whirl it into an elongated shape. The simplest explanation for the brightness variations is that two roughly spherical and equal-sized bodies eclipse each other periodically every 6.89 hours, which means they must be very close together. We view them along their equators, which maximizes the eclipsing effect.
*Hmmmm...check out the radar reflections image from Arecibo (a main-belt asteroid, not a KBO). Intriguing.
Sheppard and Jewitt have found other possible contact-binary Kuiper Belt objects (KBOs). Given the number of KBOs they have observed, and the fact that other KBO contact binaries might be viewed pole-on (which makes them harder to categorize), Sheppard and Jewitt estimate that at least 10 to 20 percent of all large KBOs might be contact binaries with similarly-sized components.
--Cindy
We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...
--John Sladek (The New Apocrypha)
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