Infant planetary system has planets orbiting in opposite directions

[sol_g2v]

This (http://www.spaceref.com/news/viewpr.html?pid=18998) is rather bizarre.

[Tobin Dax]

This (http://www.spaceref.com/news/viewpr.html?pid=18998) is rather bizarre.

Very bizarre and very interesting. I'll have to keep an eye out for that article, especially since Tony Remijan was here for the first couple years I was.

[Launch window]

very strange and likley to be a rare event ,
but can they be sure that these are planets and not some cloud asteroid or cloud of comets

[Blob]

Hum,
IRAS 16293-2422 is a low-mass star forming region located in the  Ophiuchus cloud complex at a heliocentric distance of 160 pc.
The counter-rotating protostellar accretion disk is probably the result of swirling clouds rotating in different directions in the star-forming region.

Position2000): RA = 16h32m22s.875, Dec = -24o28'32''.48

http://arxiv.org/PS_cache/astro-ph/pdf/0512/0512225.pdf

[Ara Pacis]

The story says that this is unusual and that it is different than the way the solar system formed. Do we know that for a fact? I was thinking that two counter rotating dust clouds might cause more frequent and energetic collisions in the mid range of the disc. The planet formed at this collision area might end up being one of the larger ones, that might cause tidal effects (eddies) in both discs. I wonder if this large middle planet might end up flinging some of the outer planetoids into the inner disc, where they are slowed down by head-on impacts. These impacts might be so energetic that the heavier elements remain within the Roche limits while gaseous type material gets ejected and drifts to the outer disc. This might result in a star/planet system with dense inner planets and large gaseous outer planets.

It's just a quick and dirty hypothesis. It might be another factor to plug into the Drake Equation too. Forget the Rare earth idea, the entire system formation may be rare.

[Tacitus]

I suspect that, for the next few years at least, there will be almost as many surprises as there are solar systems discovered. We have a reasonable handle on the general theory of system evolution, but the devil is obviously in the details. Should be fun finding out though!

[Romanus]

A planetary system like this would be fascinating--for what it's worth, it seems that planets in retrograde orbits (relative to prograde neighbors, of course) are more stable, IIRC. This could allow for some really interesting orbital scenarios...

[Blob]

Hum,


The solar system of IRAS16293-2422 that will probably form around this young star, will have the innermost planets orbit in one direction and the outer planets will orbit in the opposite direction.

"Similar structures and dynamics commonly occur on small and large scales throughout the Universe. Thus, it is not surprising to find counter-rotation in a protostellar disk since the phenomenon has been previously reported in the disks of galaxies" - Jan M. Hollis, NASA Goddard Space Flight Centre.

http://www.nrao.edu/pr/2006/counterdisk/

[Doodler]

This (http://www.spaceref.com/news/viewpr.html?pid=18998) is rather bizarre.

Not so bizarre, even this system had them. Take a look up in the sky and see the results of retrograde proto-planets.

[Ara Pacis]

Doodler, are you referring to retrograde revolutions or retrograde rotations?

[Doodler]

Doodler, are you referring to retrograde revolutions or retrograde rotations?

Nope, the Moon. Current theory has it being formed after a glancing impact between Earth and a Mars sized planet orbiting in the opposite direction (retrograde). While time has left us with a system full of prograde survivors, its apparent these were not the only candidates in the early life of the Solar System.

[sol_g2v]

I think it is the discovery of prograde and retrograde planets that appear to be capable of surviving beyond the formation stage that is unusual. It's as if all the rocky planets in our solar system were orbiting in one direction and all the gas giants in the other.

[Kullat Nunu]

The object which collided with Earth may have formed in either of Earth's Trojan Lagrarian points. When it grew too massive, its orbit became unstable and it started to oscillate around the Lagrarian point. Eventually it left the point and drifted into a collision course.

[TravisM]

Yeah, I never heard of the moon-creating-impactor orbiting the opposite direction. I suppose it's possible, but a glancing shot from a relatively slow planet (overtaking the protoearth's orbit) would result in the moon more so than a head on collision which would, more than likely, end up with a single planet with no moon to speak of.
Just my loose change on the subject...

[Doodler]

Yeah, I never heard of the moon-creating-impactor orbiting the opposite direction. I suppose it's possible, but a glancing shot from a relatively slow planet (overtaking the protoearth's orbit) would result in the moon more so than a head on collision which would, more than likely, end up with a single planet with no moon to speak of.
Just my loose change on the subject...

IIRC, the simulations run indicated a head on collision most often generated two moons.

[Kullat Nunu]

The object which collided with Earth may have formed in either of Earth's Trojan Lagrarian points. When it grew too massive, its orbit became unstable and it started to oscillate around the Lagrarian point. Eventually it left the point and drifted into a collision course.

See the story of Theia (http://en.wikipedia.org/wiki/Theia_%28planet%29) and Giant impact theory (http://en.wikipedia.org/wiki/Giant_impact_theory). The latter page has a cool animation which nicely illustrates the idea.

[Ara Pacis]

Ah, I was gonna post that link to wikipedia, too. I think that shows that the collision was not so much head on, and it was the first planet hitting the brakes and the earth rear-ending it.

I'm still not sure I like calling it Theia. I'd prefer to call it Luna, since part of it may be still original to the moon. This would make the moon a remnant Twin Planet, instead of a double planet or moon.

But I digress. I wonder if the counter-rotatnig discs is more likely to result in a system like ours and if systems that had a mono-disc tended to result in a few large jovians in close orbits.

[Kullat Nunu]

It was not a head on collision, otherwise the proto-Earth would have been shattered and reassembled into a single body. It is important for the Giant impact theory that the impactor came in a very shallow angle and with very slow speed in relative to the Earth. The Theia theory explains nicely how such object was formed and how the impact was possible.

I like to call it Theia, who was a titaness and mother of the moon goddess Selene in the Greek mythology. The name Luna refers to our Moon itself.

[Mungascr]

Thanks for the link and discussion. Interesting and thought-provoking - seems we still know so little and guess so much. Therein, naturally, lies the fun.

Couple of thoughts : Could a head-on explain why Ouranos * orbits on its side compared to the other planets and the Sun?

Could it explain why Venus orbits upside down so the Sun rises in its West rather than its East?

&

Could this be one process (Counter-rotating disks) that robs planetary forming material of angular momentum and kinetic energy and thus drives planets inwards creating a system of hot Jupiters? Do head on collisions with other proto-planets or streams of asteroids, comets, dust and planetesmals mean the proto-planets 'stall' and thus falls inwards?

If so, does this mean Hot Jupiters are created by such rare systems and does this tally with the percentage of hot Jupiters discovered -about 5% of stars I understand so far? So can anyone shed light on :

How many protoplanetary discs do we know of that are like this?
What % are they of the total protoplanetay disks? &
Does that equate to the known % of HotJoves?

- Just thinking aloud and writing it down.

* Ouranos = Uranus - its a better name I've chosen to use because it is closer the origianl Greek word for the Roman god Chronos and I'm justsick unto deathof all the bad so-called jokes about the name of the planet between Saturn &Neptune -see separate thread.