Niku Is A Rebel From The Oort Cloud

Niku is an object that orbits our Sun, but at a great enough distance to be considered a “trans-neptunian object”. Objects with an average orbital distance from the Sun greater than the orbit of Neptune (at 30 AU), earn this tag. Niku is likely to be a chunk of rock, but it might also contain ice. This will not become obvious soon, because Niku will not cross over the frost line (around 3-4 AU) where the heat from the Sun melts ice and evaporates it. The size of Niku is estimated from brightness measurements at between 70 and 250 kilometers in diameter.

The rings of Saturn all orbit the planet in the same flat disc or plane. The planets of our Solar System also orbit the Sun in a flat plane. This is normal for systems that form while rotating. But Niku does not conform to that plane, instead, orbiting on a plane that is inclined by nearly ninety degrees to the rest of the system.

This steeply inclined orbital plane is an indication that Niku may be from the Oort Cloud instead of the Kuiper Belt, because KB objects tend to conform to the normal plane of the Solar System, while the Oort Cloud is a larger spherical group that surrounds the entire system from every angle.

Niku orbit-diagram

Niku orbit-diagram

(471325) = 2011 KT19 – [IAU Minor Planet Center]

Retrograde Rock “Niku” Defies Orbital Trend – [skyandtelescope.com]

This isn’t your parents solar system — or even the tidy one you memorized in primary school. In addition to the classic, orderly inner and outer planets, you can now add a bewildering menagerie of Trojans, Centaurs, Kuiper Belt objects, and more.

As a case in point, a recent discovery could hint at a distinct new class of high-inclination Centaurs lurking in the distant solar system. “Centaurs” are objects whose orbits cross those of one or more outer planets. They generally lie this side of the Kuiper belt but beyond Jupiter.

The object in question is 2011 KT19, which has now been assigned the number 471325 by the IAU’s Minor Planet Center. Observers with the Mount Lemmon Catalina Sky Survey first spotted it in 2011. Then it turned up again last year in images taken with the PanSTARRS 1 telescope in Hawai’i, and a team led by Ying-Tung Chen (Academia Sinica, Taiwan) derived the object’s orbit and announced its findings this month.

SEE ALSO:
The Difference Between Asteroids, Comets, and Dwarf Planets

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