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Christoast
2009-Mar-26, 02:11 AM
What happens when a solar system dies (the star died without going nova) Do they just keep orbiting forever or are there just dark planets randomly flying everywhere, we just cant see them? Maybe that's what the missing gravity causing dark matter is from? [obviously that can't be true but I thought i'd ask anyway]

I have no idea - I've watched probably 100s of documentaries but haven't really seen anything cover this topic.

01101001
2009-Mar-26, 02:41 AM
What happens when a solar system dies (the star died without going nova)

Welcome to BAUT Forum.

Maybe you'd enjoy such as Wikipedia: Stellar evolution (http://en.wikipedia.org/wiki/Stellar_evolution) and learning how few non-nova stars have died -- mainly due to lack of time.

Maybe some distant, distant day.

Swift
2009-Mar-26, 02:52 AM
A star like our sun will go through a red giant phase. During that time it will engulf the inner planets, at least out to Venus, and probably Earth too. After that it will shrink back down to a white dwarf. The outer planets should just continue to orbit it, assuming nothing else disturbs them.

Jens
2009-Mar-26, 02:58 AM
What happens when a solar system dies (the star died without going nova) Do they just keep orbiting forever or are there just dark planets randomly flying everywhere, we just cant see them?

As a simple answer, orbiting planets do not in any way require the sun to be carrying out fusion -- they only need the mass. So whether the sun is generating power or not is not an important issue. If the star collapses into a white dwarf, any planets that survive the period before that will simply continue to orbit.

Christoast
2009-Mar-26, 03:20 AM
so is it possible that these dead and dark solar systems are causing the unexplained gravity?

01101001
2009-Mar-26, 03:37 AM
so is it possible that these dead and dark solar systems are causing the unexplained gravity?

Wikipedia: Dark matter (http://en.wikipedia.org/wiki/Dark_matter):


Other possibilities involving normal baryonic matter include brown dwarfs or perhaps small, dense chunks of heavy elements; such objects are known as massive compact halo objects, or "MACHOs". However, studies of big bang nucleosynthesis have convinced most scientists that baryonic matter such as MACHOs cannot be more than a small fraction of the total dark matter.

Amber Robot
2009-Mar-26, 04:03 AM
Furthermore, I believe that the MACHO microlensing survey put an upper limit on how much dark matter these can account for.

EDG
2009-Mar-26, 05:35 AM
The outer planets should just continue to orbit it, assuming nothing else disturbs them.

They'll continue to orbit but their orbits would expand somehwat due to the mass loss from the star between red giant and white dwarf stages.

astromark
2009-Mar-26, 07:57 AM
Thanks to EDG my point has been made: Him's is cweva...:)
That some expansion of orbits would result from the decreased mass of the parent star. Being the mass that is being orbited. Any small stable star that will not have a nova event has so little mass as to not throw off layers of itself it will just whimper out and cool. Not changing mass equals not altering the orbital mass... nothing changes. Our star the sun is not going to just go out. When it has reached that point where it has converted most of its hydrogen into helium it will become un-balanced internally. It will begin to expand as it no longer has the mass to hold onto all its matter and mass will be shed. Its during this phase that Mercury Venus and Earth will be bombarded with much expelled solar mass. Temperatures will rise to be life extinction levels long before the expansion of sol engulfs Earth. All of which is just a few billion years away yet.
I am sure that this idea of dead stars being the stuff of dark matter is itself dead in the water. We call it 'dark matter' because we do not know what else to call it. We do not know what it is. If we thought it dead stars we would call it so. we do not, it is not. Just as we do not know what 'dark energy' is. Other than to say its the opposing force to gravity.
I am interested in why you think its so simple?.:) Do you not think we might have considered this thought before,? Some force as yet not well understood is pulling this universe to infinity, and its getting faster as it goes... We do not know what else to call it. So it got the 'dark' word added to calm the need to better name these things. We are on the brink of a better understanding as the 'Higgs Boson' particle is tested... mark.

GOURDHEAD
2009-Mar-26, 01:14 PM
The remnant sun and the remaining planets are gravity wells into which interstellar dust and gas will continue to fall, and, given enough time, will light up again---hence a new heaven and a new Earth.

phunk
2009-Mar-26, 04:35 PM
The remnant sun and the remaining planets are gravity wells into which interstellar dust and gas will continue to fall, and, given enough time, will light up again---hence a new heaven and a new Earth.

I don't think you can get a new star from infalling gas on an old star remnant. A white dwarf that slowly accretes additional gas will explode in a type 1a supernova. Not sure what happens with a neutron star but I imagine the accreted gas would occaisionally explode once enough built up. And a black hole certainly can't become a star again. Are there any other types of stellar remnants?

Disinfo Agent
2009-Mar-26, 05:54 PM
Just for you: The Sun as a White Dwarf (http://www.bautforum.com/universe-today-story-comments/86079-sun-white-dwarf-star.html). :)

kzb
2009-Mar-27, 04:27 PM
I believe a post-red giant phase planet has been found orbiting a white dwarf, and it should have been engulfed. So it looks like the event is survivable, at least to the body of the planet.

There are also plenty of exoplanets in very close orbits, but they seem to survive.

rommel543
2009-Mar-27, 05:09 PM
So if earth isn't A) swallowed by the sun as it expands, or B) thrown off into space by changes in gravity, then it will be bombarded by asteroids. Weee..

The article stated that there is a possibility that the outer planets' orbit may increase to the point that they are no longer tied to the Sun (unless I read it wrong) and be thrown into interstellar space. Would it be possible for another star system to capture the rouge planets?

astromark
2009-Mar-28, 08:33 AM
Its not imposible... just not likely as space is so very big and so very empty...
a planet could be thrown out into the void to never get so close to any star as to significantly be effected.
So I would say...No. It becomes Galactic Debris.

AndrewJ
2009-Mar-28, 06:30 PM
Its not imposible... just not likely as space is so very big and so very empty...
a planet could be thrown out into the void to never get so close to any star as to significantly be effected.
So I would say...No. It becomes Galactic Debris.

Really? There are 37 stars within 15 light years of us, for instance. I would have thought that a planet that was ejected from its system on the demise of the star and then sailed off for a few hundred thousand years probably would pass close to another star and get effected, even if the planet wasn't originally in a cluster. This assumes that its original system was not on the fringe or halo of a galaxy.

astromark
2009-Mar-28, 07:18 PM
They will not be traveling at c. So the time period to pass through your 15 LY radios is going to be millions of years. What ever direction your planet is tracking takes it away from 80% of your 35 stars. The closeness of stars is so thin, spars. that two whole Galaxies can pass through each other without a single stellar collision. That seemingly tight clusters of stars never have collisions. I can only repeat that space is almost empty. The space between objects is enormous. No we are not talking of things on the fringe of the galaxy. Further more its almost impossible for a free passing object to be captured and enter a stable orbit. The velocity and trajectory must match the mass, gravity force and, it just does not happen that way. You do not seem to comprehend how empty space is. This Galaxy 'The Milky Way' has but 400 million stars. (approx). when you consider the area that it is defused into... a rouge planet could pass right through and never get close to a star. BUT. It could also smack right into one. The 'window' for orbital capture is tiny., and space is so very Very big.

cjameshuff
2009-Mar-28, 07:38 PM
Really? There are 37 stars within 15 light years of us, for instance. I would have thought that a planet that was ejected from its system on the demise of the star and then sailed off for a few hundred thousand years probably would pass close to another star and get effected, even if the planet wasn't originally in a cluster. This assumes that its original system was not on the fringe or halo of a galaxy.

37 stars within 15 light years...but systems are tiny targets. Neptune, for instance, is only about 0.00047 light years away from the sun, making a small target on the scale of interstellar distances. Looking at the cross sections, it works out to be almost exactly a 1 in 1 billion chance for a trajectory through a 15 light year radius (cylindrical) volume to pass within 30 AU of a given point.

Neptune also takes 165 years to complete an orbit, at 5.4 km/s. A rogue planet is almost certain to be moving many times faster than that, and will have to nearly collide with the star to be affected strongly by it. It would also have to both make a close pass with a star at unusually low relative velocity and make a close encounter with a planet of that star to be captured, and planets are tiny targets even on the scale of a solar system...it's rather more likely with a binary system, but it's also more likely to get thrown back out of the system.

So, if it does manage to make a close pass with another system, it is almost certain to sweep past it at high speed, spending a matter of decades, years, or even just months within the system, and departing the system without being greatly affected or greatly affecting anything in the system.

AndrewJ
2009-Mar-28, 08:32 PM
it works out to be almost exactly a 1 in 1 billion chance for a trajectory through a 15 light year radius (cylindrical) volume to pass within 30 AU of a given point.

OK, I was wrong, there is very little chance of a delinquent planet encountering another star. I find the image of a dark object sailing unopposed through the void like a ghost ship quite appealing.




You do not seem to comprehend how empty space is.

I am chastened and rebuked. I shall mediatate on the emptiness of space. :silenced:

astromark
2009-Mar-28, 09:29 PM
OK, I was wrong, there is very little chance of a delinquent planet encountering another star. I find the image of a dark object sailing unopposed through the void like a ghost ship quite appealing.

I am chastened and rebuked. I shall meditate on the emptiness of space. :silenced:


You seem to have now grasped this notion well.... :) Do not ever stop asking questions.
Not rebuked or chastised... just guided, a... mark.

kleindoofy
2009-Mar-28, 09:51 PM
What happens when a solar system dies ...
Just food for thought:

We all seem to have the notion that when a sun uses up it's hydrogen, i.e. up the critical point that the major fusion action is reduced to a very low state (red giant, white dwarf), that the sun has "died" and its solar system along with it.

Another perspective might be to say that such solar systems have reached maturity after a stormy youth.

One could also view the huge stars that become super novae as over-sized jocks on steroids that explode before reachung adulthood. ;)

galacsi
2009-Mar-29, 05:56 PM
Good solar systems go up to Heavens and bad ones go down to the bottom of a black hole . :rolleyes: :whistle:

Disinfo Agent
2009-Apr-20, 02:11 PM
UT article: Ancient Solar Systems Found Around Dead Stars (http://www.bautforum.com/universe-today-story-comments/87363-ancient-solar-systems-found-around-dead-stars.html).

fifelad55
2009-Apr-22, 05:14 PM
Good solar systems go up to Heavens and bad ones go down to the bottom of a black hole . :rolleyes: :whistle:

I beg to differ. The bad ones come to Pattaya where I live. :lol

A question. Suppose a Jupiter mass planet has been expelled from it's solar system, how close would it have to pass to, say, a black hole with a mass of 10 times that of the Sun to be captured?

Alan

01101001
2009-Apr-22, 06:00 PM
A question. Suppose a Jupiter mass planet has been expelled from it's solar system, how close would it have to pass to, say, a black hole with a mass of 10 times that of the Sun to be captured?

Do you mean how much kinetic energy must it lose so that it might enter into orbit, where otherwise it might have passed freely by on a one-pass hyperbolic orbit?

I think that all depends on its original energy and the methods available to it for shedding that energy. Will it encounter lots of mass, dust, gas, larger bodies? Does it have moons to toss away to lower its energy? What speed relative to the black hole does it have? How close does it come to the black hole?

(Black holes are just lots of mass in a compact, tiny package. They don't have special abilities to reach out and grab passing objects. Generally, for objects entering from outside a system, capture is not a typical outcome, no matter the type of object at the center.)

galacsi
2009-Apr-22, 06:52 PM
Do you mean how much kinetic energy must it lose so that it might enter into orbit, where otherwise it might have passed freely by on a one-pass hyperbolic orbit?

I think that all depends on its original energy and the methods available to it for shedding that energy. Will it encounter lots of mass, dust, gas, larger bodies? Does it have moons to toss away to lower its energy? What speed relative to the black hole does it have? How close does it come to the black hole?

(Black holes are just lots of mass in a compact, tiny package. They don't have special abilities to reach out and grab passing objects. Generally, for objects entering from outside a system, capture is not a typical outcome, no matter the type of object at the center.)

IMO you are mostly right BinaryMan , but if this jovian planet pass too close the BH , it will be disrupted by tidal forces. A little bit of the planet will be captured and digested.

Joe Meils
2009-Apr-22, 07:57 PM
Its not imposible... just not likely as space is so very big and so very empty...
a planet could be thrown out into the void to never get so close to any star as to significantly be effected.
So I would say...No. It becomes Galactic Debris.

True. I was reading an interesting article recently that said that even in the case of two galaxies colliding, there would be few (if any) individual stars in collision, or even passing close enough to disrupt any bodies that might be orbiting them...

It would be as if two clouds of gnats were to pass through one another... (except that anology is flawed... the gnats would be vastly closer together than the stars would be)

The gross effect of the gravity wells would definitely disrupt the structure of both galaxies, however... sending at least some of the solar systems within them out into the void of extra-galactic space...