Sedna May Have A Moon

ArrayIndexOutOfBound writes "The newly found planet Sedna may have a moon. It appears that most astronomers argue that Sedna is only another proof that neither Sedna nor Pluto are really planets. Interestingly, the planet has been found by an 'automated sky survey telescope'..." SYSS Mouse points to a NASA page with more information about "our potential 10th planet. ... It is 130 billion miles away from the sun (900 times Earth's distance from the sun) and has a 10,500 years orbit, compared to Pluto's 230 years around the sun."

Comments

Value out of bounds

[shadowbearer]

Um, the article said it was 13 billion miles out, not 130 billion (now discovering something that size 130 billion miles out would be a real hell of an achievement :)

There's some theorizing that this may be part of the inner Oort shell; I think it more likely that at that distance it's an outer member of the Kuiper bodies.

Given the highly elliptical orbit, it's size, and it's apparently odd surface color, it's also possible that it's a body captured by the sun some hundreds of millions or billions of years ago. Now *that'd* be neat.

SB

Re:Value out of bounds

[Pumpernickle]

That's true, but not entirely.

At its most distant, Sedna is 130 billion km (84 billion miles) from the Sun, which is 900 times Earth's solar distance (149 million km or 93 million miles).

They were just quoting the wrong part of the article in the wrong place.

Re:Value out of bounds

[IamNotWitchboy]

From an article about Sedna featured on Scotsman News International appeared on Google News which displays the following paragraph:

Dr Michael Brown, an astronomer at the California Institute of Technology in Pasadena, who led the NASA-funded research, said: "The sun appears so small from that distance that you could completely block it out with the head of a pin."

The temperature on Sedna never rises above -400C, making it the coldest known object in the solar system.

It must be an extremly bizarre planet because its temperature is WAY below the absolute zero which is known to be at -273 C

Re:Value out of bounds

[phyrestang]

I should think that it was a typo. They probably meant -400F, as absolute zero is -459 Fahrenheit.

Incorrect links

[Rewbob]

The first link is about an object named "2004 DW". The second link is about Sedna (previous known as 2003 VB12).

The newly found moon is orbiting Sedna, NOT 2004 DW.
The links in the slashdot article are misleading.

Re:Incorrect links

[kalidasa]

They haven't actually *found* a moon around Sedna yet, they're just guessing there's one there because the rotational period is very slow, suggesting that it might have a relationship with a satellite similar to Pluto's with Charon. 2004 DW is another big object (TNO).

Re:It's too far out to be an SKBO

[shadowbearer]

From the same page:

Is Sedna an Oort Cloud Comet?
From the Classical Oort Cloud - no. The latter consists of objects whose orbits are so large (50,000 AU) that passing stars and galactic tides can alter their properties. Sedna doesn't travel very far out (1000 AU) and is effectively immune to external forces. Also, the inclinations of both Sedna and 2000 CR105 are small (12 and 23 degrees, respectively). These objects know where the plane of the solar system lies. Oort Cloud orbits are random with inclinations all the way up to 180 degrees.

So What Is It?
Sedna could be a member of a substantial population of bodies trapped between the Kuiper Belt and Oort Cloud. These would have been emplaced at early times and unseen until recently. 2000 CR105 and Sedna are "just the tip of the iceberg", as they say. The scientific interest lies in how these objects had their perihelia lifted out of the planetary region.

So it's really on the fuzzy boundary between the two, but closer to the Kuiper belt than to traditional Oort cloud objects. I'd bet there are a lot more objects this close to this size out there. (a hunch, but we're only beginning to explore that region).

Fascinating. I wonder if we'll ever trace it's orbit back far enough to determine whether it was flung out of the inner system or formed elsewhere. Doubtful. In any case, it's good to know there are objects this size out in that region, just in case we ever *really* need to flee the inner system (tongue in cheek, partially; reading the news gives me that feeling often nowadays..)

SB

Re:Sedna has a moon...

[adeyadey]

Many (non-planet) Asteroids have moons or satellites in orbit about them..