Orphan planets, i.e., planets not in a solar system

In summary, astronomers have discovered a potential "rogue" alien planet wandering alone just 100 light-years from Earth. This planet, CFBDSIR2149, is likely a gas giant planet four to seven times more massive than Jupiter.
  • #1
Astronuc
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Orphan or 'rogue' planets may be common, rather than an exception, at least in the galaxy.
http://news.yahoo.com/orphan-alien-planet-found-nearby-without-parent-star-122308193.html

Astronomers have discovered a potential "rogue" alien planet wandering alone just 100 light-years from Earth, suggesting that such starless worlds may be extremely common across the galaxy.

The free-floating object, called CFBDSIR2149, is likely a gas giant planet four to seven times more massive than Jupiter, scientists say in a new study unveiled today (Nov. 14). The planet cruises unbound through space relatively close to Earth (in astronomical terms), perhaps after being booted from its own solar system.

. . . .

But how common?
 
Astronomy news on Phys.org
  • #2
I'm thinking that the best way to figure out how probable this is, at least without actually observing a large number of rogue planets (which I think would be a waste of effort, seeing as how we would essentially have to aim telescopes into random points in space), would be to determine in what ways a planet could be cast out from its solar system, and then to determine how likely those occurrences are from what we already know.

Not that I really know anything that would cause something like this to happen other than a large gravitational force, but I don't see how we could figure out the probability of the occurrence of rogue planets any other way.

Then again, astronomers could possibly focus heavily on one area, and find how many rogue planets are in that given area. Assuming that these planets haven't drifted too far from their solar systems, this could then be applied to other similarly populated areas (in terms of the number of stars).
 
  • #4
Do they need a star system to be produced in the first place? If my understanding is right gas giant can be produced just by the small collapsing gas cloud, and the difference between gas cloud collapsing into a star or a gas giant would be only its initial size?

In the case of other planets (other than gas giants) that's not that easy, as apparently you need a star system for the elements to separate.
 
  • #5
That is certainly possible, but, my impression is most are ejected. Free forming bodies are usually termed sub-brown dwarfs.
 
  • #6
AnTiFreeze3 said:
which I think would be a waste of effort, seeing as how we would essentially have to aim telescopes into random points in space),

But we already do this. We call them surveys.
 
  • #7
AnTiFreeze3 said:
I'm thinking that the best way to figure out how probable this is, at least without actually observing a large number of rogue planets (which I think would be a waste of effort, seeing as how we would essentially have to aim telescopes into random points in space), would be to determine in what ways a planet could be cast out from its solar system, and then to determine how likely those occurrences are from what we already know.

Perhaps most rogue planets never orbited primary stars, but formed as pieces of collapsing nebula independent of any stellar formation. Failed protostars.
 
  • #8
Pasha582 said:
Perhaps most rogue planets never orbited primary stars, but formed as pieces of collapsing nebula independent of any stellar formation. Failed protostars.

I claimed ignorance in this area of expertise (along with most). I'm certain that there are other ways that they can form besides what I mentioned.

Regardless, Borek already brought it up:
Borek said:
Do they need a star system to be produced in the first place? If my understanding is right gas giant can be produced just by the small collapsing gas cloud, and the difference between gas cloud collapsing into a star or a gas giant would be only its initial size? ...

Vanadium 50 said:
But we already do this. We call them surveys.

I wasn't aware of that, thanks.
 
  • #9
we are still in the process of plantery discovery. it is amazing how over a decade our view of plantery systems has come along. it is now belived that 'average' 1-5 solar mass stars of which there are plenty have matured planets orbiting them.
plantery systems are usually in elliptical orbits and over a period of time certain unfavorable resonences will be created that WILL cause oribital migration.
it will also happen in our system over time as well.
there are bound to be many many rogue planets.
but due to the small size they are at the moment unable to be detected.
 
  • #10
Just saw a presentation that included this very subject last night at the Cleveland Museum of Natural History. It was a talk given by a professor at Vanderbilt. He claimed that estimates are around 1.6 rogue planets per star. That's a lot of planets! Hopefully, none are named Melancholia.
 

1. What are orphan planets?

Orphan planets, also known as rogue planets, are planets that do not orbit a star and therefore do not belong to any specific solar system. They are free-floating in space.

2. How do orphan planets form?

There are a few theories on how orphan planets form, but the most widely accepted one is that they are ejected from their original solar system due to gravitational interactions with other planets or stars.

3. Are orphan planets habitable?

It is possible for orphan planets to be habitable if they have the right conditions, such as a suitable atmosphere and liquid water. However, the chances of finding habitable orphan planets are very low.

4. Can we detect orphan planets?

Yes, we are able to detect orphan planets through various methods such as gravitational microlensing, direct imaging, and radio emissions. However, these methods are not as effective as detecting planets within a solar system.

5. Could an orphan planet support life?

It is possible for an orphan planet to support life, but it would be a very challenging environment for life to thrive in. Without a nearby star, the planet would not receive any warmth or light, and it would be difficult for it to sustain an atmosphere. However, there is still much we do not know about orphan planets, so it is not impossible for them to support life.

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