# Intergalactic rogue stars?



## matt-browne-sfw (Oct 15, 2007)

There are a lot of interesting theories about so-called rogue planets in the Milky Way, existing in interstellar space... totally dark worlds far away from any sunshine. Very plausible.

Would such a phenomenon also occur in the vast empty voids of intergalactic space? Would there be any shining stars say half-way from the Milky Way to Andromeda? Rogue stars so to speak?


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## Joel007 (Oct 15, 2007)

I'm sure some of the stars on the ends of the spiral arms could easily be classes as rogues, it depends on how far out they are. 

I'd probably class a rogue star as one so far from any other masses as to be virtually unaffected (as far as it's velocity was concerned). Then again, is that even possible considering the size of your average star?

And I like to class large cold rogue planets as "bigass asteroids"


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## gully_foyle (Oct 16, 2007)

That's a good question. Galaxies are large accretion disks, sort of like solar systems on a bigger scale. They have gravity so they would suck up any inter-galactic hydrogen. But, that's not to say there wouldn't be any inter-galactic hydrogen that might escape the pull of the nearest galaxy, accrete into a disk and form a solar system. The other scenario would be a star escaping a galaxy, which I would imagine would be pretty hard to achieve. It would need to have sufficient velocity to overcome the galaxy's gravity. Unless, there was another galaxy nearby that was pulling on the star. Galaxies do collide and there are some pretty neat pictures of them doing that. Maybe your rogue star could be a pre-cursor to a galactic collision.

If you want a professional opinion try here... Curious About Astronomy? Ask an Astronomer


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## Nik (Oct 17, 2007)

No problem.

All you need is for big star in a close-binary system to go super-nova, lose much of mass. Second star still has orbital velocity but no heavy partner to match, goes flying at near-tangent.

IIRC, such 'widows' can have galactic-escape velocities. 100 miles per second is common, 350 not unknown...


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## matt-browne-sfw (Oct 17, 2007)

Nik said:


> No problem.
> 
> All you need is for big star in a close-binary system to go super-nova, lose much of mass. Second star still has orbital velocity but no heavy partner to match, goes flying at near-tangent.
> 
> IIRC, such 'widows' can have galactic-escape velocities. 100 miles per second is common, 350 not unknown...



Good point. Well, our telescopes can focus on individual stars in the Andromeda galaxy. This means - because a rogue star is much closer - we should be able to find one with a telescope. Have we?


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