New Model Helps Predict Earth-Sized Planets

look over yonder writes "A new computer model created by astronomers from the Smithsonian Center and Astrophysics and the University of Utah predicts that systems which harbour Earth-sized planets will have a fingerprint of a ring of dust orbiting the star. This model will make it much easier for astronomers to locate stars and predict the size of planets orbiting it by simply measuring how bright the star system is at infrared (IR) wavelengths of light. Stars with dusty disks are brighter in the IR than stars without disks. The more dust a star system holds, the brighter it is in the IR."

Absorption/re-emission?

[aurum42]

Unfortunately the article is a little light on details. Presumably the IR signature is due to absorption and re-emission by the dust cloud, but I'm curious as to how they distinguish between a "normal" dust cloud and one that's due to an Earth sized planet. Interesting.

Re:Absorption/re-emission?

[Anonymous Coward]

As I understood it from the article. The IR signature is due because in a planet forming protoring, small planets wip asteroids etc around in gravity slingshots, in the long term this means alot of those asteroids will smash together at very high speed, basically blowing each other up into lots of hot dust, and as such, lots of infrered radiation.
I figure the rate at which this dust is formed, correlates to the weight of the planets doing the slingshotting, thus getting you a specific IR signature.

Quicksho

Re:Absorption/re-emission?

[ktanmay]

I wanted to incorporate the details, but just didn't know how to, anyway, if you want details, here you go [harvard.edu].

Re:Absorption/re-emission?

[ktanmay]

Forgot to add this [harvard.edu].

Re:Absorption/re-emission?

[Tau Zero]

I'm curious as to how they distinguish between a "normal" dust cloud and one that's due to an Earth sized planet.

The article states "The size of the largest objects in the disk determines the dust production rate. The amount of dust peaks when 600-mile protoplanets have formed." The dust forms in roughly the same orbit as the planet, so presumably you could detect a protoplanet forming at an Earth-like distance by watching for dust at a temperature of ~250 K; if there was the amount of dust you'd expect from an 8000-mile planet (well down from the peak at the 600-mile planetoid size), you might well have something like the prototypical Earth in that orbit.

I'm not sure how useful this is going to be in locating habitable planets; getting to them long before the intense bombardment phase has stopped isn't going to make for good colonization prospects. On the other hand, as a way of calculating the prevalence of Earth-like planets this is a huge breakthrough.

Re:Absorption/re-emission?

[Pumpernickle]

I'm not sure how useful this is going to be in locating habitable planets; getting to them long before the intense bombardment phase has stopped isn't going to make for good colonization prospects.

They're just planning ahead for when they think they'll have a working interstellar space program. By then, it will be easier to meet the non-earthlings halfway, too. :)

Finding life?

[Via_Patrino]

"predicts (...) systems which harbour Earth-sized planets"

I don't think that's not the only way of finding life or an enviroment friendly to humans. Earth-sized moons of big planets can have a more friendly enviroment than earth-sized planets.

Yet again, maybe not

[AtariAmarok]

Earth-sized moons of big planets can have a more friendly enviroment than earth-sized planets.

Or maybe they can't. We've only found one planet with a friendly environment so far, and this is really too small of a dataset to generalize.

Big honkin' Van Allen belts

[Latent Heat]

Given the "hot Jupiters" found orbiting nearby stars, there is nothing to say that a gas giant as to be 5 AU out -- you could have one in Earth's orbit with habitable moons all around.

But Jupiter has a strong magnetic field and an intense set of radiation belts through which its moons orbit. It would be a reasonable assumption that a gas giant would have a strong magnetic field as it probably has a core of hydrogen in some kind of superfluid, conducting state (compressed liquid hydrogen, metallic hydrogen, and other hypothesized states).

Are any of Jupiter's moons colonizable from a radiation standpoint?

Re:Finding life?

[Tango42]

Careful, that was a double negative, so your 2 sentances contradicted eachother. I'll assume the 2nd one was what you meant, in which case, I agree. Moons of super-jovian planets could be worth looking into. They could be better, because the planet regulated things, or they could be worse because the planet confuses things. There would probably by very strong tides, because of the iteraction of the star and the planet, for a start.

Re:Finding life?

[ajax0187]

I can see the purpose of this if it's just for finding planets for the sake of finding planets. But if we're using it to see where the next intelligent life comes from, aren't we going a bit extreme? There is usually a couple billion years between when a planet is still a protoplanet and when it can sustain life. Yes, there can be millions of years between when we actually see the light from the star and the star itself (interstellar travel at the speed of light and all), but what about the systems that

Hum...

[Nimloth]

I wouldn't have thought models would be any good at science...

Timescales

[Tango42]

This method finds planets as they form, which means they will probably be billions of years away from evolving life. Although it is certainly interesting, I doubt such observations will have any direct uses. We may be able to understand our own solar system a little more by seeing how others form, but as far as finding ETIs or potential colony sites, this won't be much help. The current methods of finding planets (mainly by wobbling stars, AFAIK) is more likely to find things of interest.

Re:Timescales

[paramecio]

You are right if you think only about alien forms of life, but we have a lot to learn about the way our Earth got formed, and about its contents... And that seems a pretty good place to start :)

Re:Timescales

[Tango42]

If you read more carefully you'ld see I already said that: "We may be able to understand our own solar system a little more by seeing how others form, but..."

Re:Timescales

[paramecio]

I have to apologize as you are... just right! Next time I'll try to read more carefully. Do please excuse me! :)

By the way I am really concerned on the ETI subject, and many of my computers are running seti@home - and I'm a member of the planetary society mainly for this subject - but I really feel we are forgetting too much about the fact that we are pretty unsure about what's that thing we walk on everyday... Well, or at least discussion about this subject sounds quite faint on the net...

Maybe this feelin

Does it predict us?

[Valdrax]

Seriously, how much dust is in OUR solar system, and does this predict the existence of planetary systems like ours?

Re:Does it predict us?

[Patrik_AKA_RedX]

<rubs finger over top of monitor>
hmmm, depends on how many monitors there are in the solar system.

Re:Does it predict us?

[barakn]

That fact that meteors streak through the sky on a nightly basis is a testament to presence of dust, as are the Zodiacal Light and Gegenschein [wanadoo.nl]. Unfortunately there's not much of it. The article is about young planetary systems, which will have much more dust than our own. Mature systems will not have much of an IR component.

This is brilliant

[Free_Meson]

I'm not an astronomer, and I guess I never really thought about doing it this way, but this approach is brilliant. Assuming a suitably precise spectral analysis of IR can be made, both the size and distance of a non-gassy planet can be determined. There would be two possibilities at every value, but I would assume that a planet would suck in nearby dust and debris so that "planets" would be present where there was a deviation from the "even distribution" dust curve, and the value at that peak or valley would determine the size of the planet. The habitable zone of each planet should be relatively easy to determine, and (I assume) that a spectral analysis in the visual spectrum could verify the presence of oxygen and water.

If we ever figure out how to get up to .01c without breaking the bank, this should give us a great idea about where to send probes and, eventually, where to focus any colonisation efforts.

That being said, I think by the time we, as a people, are advanced enough to travel to another solar system, that we may not be interested in reentering a planetary gravity well once we get there...

Re: Keplar's Laws

[some guy I know]

What was wrong with Keplar's Laws?

Congress repealed Keplar's laws as part of the USAPATRIOT act.
Damn you, USAPATRIOT act!