Newfound Planet Orbits Backward

Newfound Planet Orbits Backward

news.yahoo.com

Planets orbit stars in the same direction that the stars rotate. They all do. Except one.

A newfound planet orbits the wrong way, backward compared to the rotation of its host star. Its discoverers think a near-collision may have created the retrograde orbit, as it is called.

The star and its planet, WASP-17, are about 1,000 light-years away. The setup was found by the UK's Wide Area Search for Planets (WASP) project in collaboration with Geneva Observatory. The discovery was announced

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[edit on 12-8-2009 by MysterE]

WASP-17 likely had a close encounter with a larger planet, and the gravitational interaction acted like a slingshot to put WASP-17 on its odd course, the astronomers figure.

Pretty interesting. I would imagine after time the orbit will slow to a crawl and switch rotation to match that of the star it orbits.


From this article
www.astronomynow.com

(WASP-17) is quite possibly the most bloated, swollen planet observed so far. Explaining why it is so bloated is still a bit of a mystery, but this is what makes exoplanet research so fascinating.

-E-

news.yahoo.com
(visit the link for the full news article)

[edit on 12-8-2009 by MysterE]

reply to post by MysterE

I would imagine after time the orbit will slow to a crawl and switch rotation to match that of the star it orbits.

I can think of no orbital mechanics mechanism to cause that.

The reason that most planets are orbiting in the same direction as the host star's rotation is because they were all formed from the same "cloud" of rotating material in the first place.

A planet will not slow, and then reverse orbit, all on its own. ONLY thing to alter an orbit is, as the article postulates, some outside influence.

Now this is interesting.

A retrograde orbiting planet? I'm still amazed they are finding planets, let-alone finding planets' orbits to be backwards. Good find!

I think it's either saturn or jupitor that has a moon that orbits backwards compared to every thing else in the solar system.

reply to post by wantsome


Neptune.

Triton is the largest moon of the planet Neptune, discovered on October 10, 1846 by William Lassell. It is the only large moon in the Solar System with a retrograde orbit, which is an orbit in the opposite direction to its planet's rotation. At 2700 km in diameter, it is the seventh-largest moon in the Solar System. Triton comprises more than 99.5% of all the mass known to orbit Neptune, including the planet's rings and twelve other known moons.

Because of its retrograde orbit (unique for an object of its size) and similar composition to Pluto, Triton is thought to have been captured from the Kuiper belt.

Source

reply to post by weedwhacker


Your right, it would only expierence orbital decay if it enters an atmosphere. (I think?)

-E-



[edit on 12-8-2009 by MysterE]

That is very interesting..........

I know practically nothing in this area, but it seems to me that....

Perhaps it did not form with the other planets and was captured by the star.

The path the "planet?" had was opposite of the planets formed around that star, when it was captured by gravity.

reply to post by MysterE


Thank you for posting this. This is really kewl stuff!
I just wish Pluto was still considered a planet.
Makes me wonder what else in science and history is incorrect.

reply to post by Nivcharah


Pluto will always be a planet to me!

-E-

reply to post by MysterE


I think you may be confusing it's orbital path, here, with its rotation about its axis.

At a thousand LY away, doubt there's any way (yet) to determine that.

Stars, being larger (and bright) can be observed to rotate by virtue of their surface brightness.

Still, it IS fascinating, being able to detect the planet from that far away. Re-read the article, seems they see it because its orbit is "edge-on" from out POV, allowing it to seem to cross between us and the star.

I'd guess it was captured, in some way, by the gravitational field of the host star. But accurate determination of that is full of conjecture, due to distance.

[edit on 12 August 2009 by weedwhacker]