Placement of the asteroid belt

Sporally · #1 (**permalink**) 20-September-2006, 08:44 PM

As i am a lot into exoplanets and the search for ETI, i started wondering yesterday what caused the astroidbelt and where/if we could expect to find such belts in other star systems. If you ask me, Jupiter plays a very important role in securing the prevailiance of higher intelligens. Although it throws astroids towards Earth it does indeed sweep the solar system clean of comets. I don't see the solar system as the perfect place for higher intelligens as the astroidbelt i placed between Earth and Jupiter. What i would consider the best for a star system would be to have a Jupiter sized planet or a larger planet to protect the inner planets for both astroids and comets, and this would be most efficient if you place the astroidbelt and the cometbelt on the other side of the Jupiter sized planet away from the star. So is it a coincident that the astroidbelt exists in our solar system and placed exactly where it is or could we presume where to find astroidbelts in other star systems? My guess is that there simply wasn't enough astroids to start with in the astroidbelt to form a planet (though the astroids together have the mass to form a planet the pieces are too spread for this to happen, and it is a coincident that it is placed exactly where it is). Anyone with some knowledge on this topic they can and want to contribute with?

Eckelston · #2 (**permalink**) 20-September-2006, 09:50 PM

There definitely are asteriod belts around other stars. For example the star ESO astronomers found 3 Neptune sized planets around this May has an asteriod belt and I think there are a few other known examples. My guess is that we'll find asteroid belts to be pretty common as a huge body like Jupiter will inhibit large planets from forming in its vicinity.

Doodler · #3 (**permalink**) 20-September-2006, 10:03 PM

The total sum of the mass of the belt wouldn't amount to much of a planet, and being so proximate to Jupiter keeps it nice and distributed, something akin to the shepard moons of Saturn in its ring system.

As to whether a larger planet than Jupiter would be better or not is a matter of open debate still. Would a supermassive Jovian keep too much cometary material out of the inner system, preventing water from becoming a key element in the lifecycle of the planets? Could it go the other way and actually pull more in, since its so much more gravitationally powerful? Even worse, what happens in the event of epistellar migration? Is that the deathknell of terrestrials, or does it just shake things up until it restabilizes when the migrating giant's orbit settles in?

We can detect the presence of belts, but until we get a handle on the terrestrials, its pure speculation at this point, and all concepts are still pretty much fair game.

Sporally · #4 (**permalink**) 20-September-2006, 10:32 PM

Didn't see a problem with too big Jupiters. However, my question was, unless you consider yourself to have answered the question already Doodler, if astroid belts can be predicted to be found around the same area in a standard star system that contains a sol sized star or if we can expect the astroid belt to be found randomly, more or less. So if we take a look at star systems with a Jupiter no less than 5 AUs away from its parent star, can we expect the astroid belt to be found within the Jupiter most often or is that random?

Doodler · #5 (**permalink**) 20-September-2006, 10:50 PM

Quote:

Originally Posted by Sporally

Didn't see a problem with too big Jupiters. However, my question was, unless you consider yourself to have answered the question already Doodler, if astroid belts can be predicted to be found around the same area in a standard star system that contains a sol sized star or if we can expect the astroid belt to be found randomly, more or less. So if we take a look at star systems with a Jupiter no less than 5 AUs away from its parent star, can we expect the astroid belt to be found within the Jupiter most often or is that random?

If there's a Jovian, its going to probably be there. If there's no Jovian present, its likely going to be scattered all over the place.

Sporally · #6 (**permalink**) 20-September-2006, 10:56 PM

You mean between the star and the Jovian? Too bad, would have been better if the astroid belt had been outside the Jovian. That way those astroid that are being pulled out of its orbit was more likely to hit the Jovian planet than the terrestial planet. But afterall we have seen that ETI can live with an astroid belt inside its Jovian planet

Doodler · #7 (**permalink**) 20-September-2006, 11:02 PM

Quote:

Originally Posted by Sporally

You mean between the star and the Jovian? Too bad, would have been better if the astroid belt had been outside the Jovian. That way those astroid that are being pulled out of its orbit was more likely to hit the Jovian planet than the terrestial planet. But afterall we have seen that ETI can live with an astroid belt inside its Jovian planet

Unless you've got a Jovian that migrates inbound quickly and settles into a close orbit.

Sporally · #8 (**permalink**) 20-September-2006, 11:19 PM

True, but by standard i meant situations like these was sorted away. However, i think we will find a handful of Jovians that have migrated inward, but my guess would be 10-20%. Basically just a shoot in the dark. Thx for your thought on this subject.

Doodler · #9 (**permalink**) 20-September-2006, 11:28 PM

Quote:

Originally Posted by Sporally

True, but by standard i meant situations like these was sorted away. However, i think we will find a handful of Jovians that have migrated inward, but my guess would be 10-20%. Basically just a shoot in the dark. Thx for your thought on this subject.

Its hard to call right now, because we really don't know what the true distribution of Jovians is, and its possible we'll be a century or more working it out (especially when you consider the orbital periods of the gas giants in this system). At the moment, this solar system gives you a pretty good prototype, the innermost Jovian dictates the location of the rocky belt, and the outermost would tend to dictate the location of the ice belt.

The epistellars will be your wild cards, depending on the duration involved in their inbound migration. If the move in fast, there could still be a pretty robust rock belt that could form terrestrials and asteroids. If its a slow migration, its going to literally clean house, and you probably won't see anything really form up, other than one helluva moon system. I'll bet the slow migraters have ring and moon systems that would absolutely shame Saturn and Jupiter.

Sporally · #10 (**permalink**) 20-September-2006, 11:59 PM

Epistellars? Do you think we will for a typical star system see the astroid belt and the comet belt define the areas where we can find the Jovians? Is this your own thought or do you have any papers on that subject?

Doodler · #11 (**permalink**) 21-September-2006, 12:15 AM

Quote:

Originally Posted by Sporally

Epistellars? Do you think we will for a typical star system see the astroid belt and the comet belt define the areas where we can find the Jovians? Is this your own thought or do you have any papers on that subject?

Strictly my own thoughts. As for whether its typical or not is dependent on the system in question. As we've seen here, its certainly possible.

Sporally · #12 (**permalink**) 21-September-2006, 12:17 AM

And what does the word 'Epistellar' mean?

Doodler · #13 (**permalink**) 21-September-2006, 02:06 PM

Quote:

Originally Posted by Sporally

And what does the word 'Epistellar' mean?

Not sure of the technical definition, but the layman's take is "hugging the star like a second skin". Most of the planets I've seen with this tag are within a third of the distance to its star that Mercury is to the Sun.

Sporally · #14 (**permalink**) 21-September-2006, 04:58 PM

Yeah. Their gravity makes them a lot easier to spot when they are close to their parent star, and this is how we've find most of the exoplanets.

Doodler · #15 (**permalink**) 21-September-2006, 05:03 PM

Which means for systems with planets analogous to Uranus and Neptune in this system, you and I likely won't live to see to many of them, unless they start extrapolating from partial sine curves.

Sporally · #16 (**permalink**) 21-September-2006, 11:04 PM

Well, exoplanets close to their parent stars are those we find the most of at these times, but there are some great projects coming up, some that can actually take images of the exoplanets and analyse their atmospheric chemistry if any.

Doodler · #17 (**permalink**) 21-September-2006, 11:48 PM

Quote:

Originally Posted by Sporally

Well, exoplanets close to their parent stars are those we find the most of at these times, but there are some great projects coming up, some that can actually take images of the exoplanets and analyse their atmospheric chemistry if any.

Yeah, and given that gas giants do tend towards a system's ecliptic, its outside possible that some of the more distant giants might be detectable that way.

Sporally · #18 (**permalink**) 22-September-2006, 07:54 AM

Ecliptic? You mean that they decrease the light received on Earth from that star and that way are discovered? Yeah, that's true, there are many in those orbits