sedna

[mee]

Could Sedna be a trapped rogue planet due to the nature of its distant and highly eccentric orbit? Could a trip to Sedna thus be useful?

[Nommos Prime (Dogon)]

Its orbit dictates that it MUST be a "trapped planet" or "rogue planet". If not, we'd better throw away all our theories on our Solar System's formation, because there ain't no room for a Sedna in it...

[mee]

Its orbit dictates that it MUST be a "trapped planet" or "rogue planet". If not, we'd better throw away all our theories on our Solar System's formation, because there ain't no room for a Sedna in it...

Thats cool if you are right. Maybe we could send a probe to it and find out about extraterrestrial planets. Not that it wouldnt take forever to do it and we probably wouldn't find out anything too shattering. Its still cool!

[mee]

Thats cool if you are right. Maybe we could send a probe to it and find out about extraterrestrial planets. Not that it wouldnt take forever to do it and we probably wouldn't find out anything too shattering. Its still cool!

How would it become "rogue" in the first place? Perhaps it was thrown about by a supernova and thus would have an interesting structure perhaps. It would probably be older than all our planets. Cool stuff!

[check]

Hot off the press from
http://www.newscientist.com/news/news.jsp?id=ns99996204

Sedna, the most distant planetoid ever seen in the Solar System, probably got kicked into its orbit when a star swept past the Sun more than four billion years ago, suggest the first detailed calculations of the object's origins.

[tony873004]

I think it's more likely that a passing Brown Dwarf, rather than a passing Star disrupted the orbit of Sedna. First of all, Brown Dwarfs are theorized to outnumber stars. With stars, the lower the mass, the more numerous the stars. There's no reason to believe that this trend ends at the mass critical for hydrogen fusion. So a Brown Dwarf passage is much more likely.

Also, a star, with its more massive gravity field would probably not be able to pluck Sedna from the Kuiper belt and send its Apihelion into the Oort Cloud without doing the same to most other Kuiper Belt Objects. A star passing that close would probably also introduce some eccentricity into Neptune's orbit. Yet Neptune's orbit is quite round.

On the other hand, a brown dwarf has the gravitational strength to do the job, and is capable of making a more surgical strike, affecting only Sedna and KBOs in Sedna's vicinity without disrupting much else. Perhaps Pluto was in Sedna's vicinity, but a bit more distant at the time so didn't get affected nearly as much. And Quaoar was on the other side of the Sun, where the Brown Dwarf couldn't touch it. Quaoar has a very round orbit.

Just my 2 cents :smile: