Extrasolar planets

[Shadowslayer81]

I have some questions about the various planets we've detected outside of our solar system.
I'm excited that we've found alot of them, but they descriptions of them seem rather outlandish. Like the fact that a lot of them I hear about are huge gas giants orbiting close to the host star, sometimes orbiting the stars in days. Now i'm all about seeing some weird objects out there that won't resemble our system at all, but some of the articles are hard to believe. like a resent one about a gas giant very close to the star who's atmosphere is heated to 1000c and is tidally locked. That doesn't strike me as stable at all, unless if formed very recently i'd expect it to be gone in a few million years.

Now I know were detecting a lot of these indirectly with the star wobble or by the dimming of the parent star, but given the limited amount of data you can get from those methods how do they know what they think they know. If thats the right way to put it. Now i'm sure their are planets there, but i'm not so sure they're in the same orbits or configurations they talk about. Who knows maybe they detect more normal planets but just the weird ones get all the coverage.

As far as detecting things based on the wobble of the star, which makes since. You might have an issue with lots of planets on one side of the star and just a few on the other. That would pull it more to that side making the planet look larger when its really just a couple of smaller ones. I can't quite fathom how you figure out what its orbit is when you can't even see it. Who knows maybe the star is wobbling more than it would be if it slightly imbalanced. After all stars are chaotic objects, and they spin on there own.

Anyway i could be completely wrong in my assumptions and if so feel free to correct me as i'm just trying to understand what i'm reading.

 

[MeteorWayne]

Despite your misgivings, which I understand, the detections of these extreme planets by the wobble mothod is quite robust. Pure Newtonian physics leaves no other interpretation.

The reason so many extreme (i.e. very large and very close to the star) planets have been found is that due to the method, they are the easiest and fastest to find. It's only been about a decade that we've had this data, so in observing our solar system from afar, we would not have been able to even find Jupiter (which is 75% of the mass of the solar system other than the sun), since it is in a 12 year orbit. In other words, you find the big planets in very short orbits (a year or two or less) first. That's where we are right now. Over the next decade or two we'll find smaller planets in longer orbits.

And I assure you, the mathematics involved account for the possibility of multiple planets; in fact several systems have been found with more than one planet precisely because of that.

 

[yevaud]

You'd be surprised just how much data can be inferred about those extrasolar planetary bodies via occlusion / tiny eccentricities of the primary. Certainly we can infer the approximate mass of the body in question via the "wobble," for example. We can also infer the approximate dimensions of said body via the amount of light occluded.

As Wayne said, one day soon, our optical resolving power will have increased by a magnitude, and then we will be able to perhaps actually image some of these planets, and certainly detect Earth-mass planets as well.

One concept - I hope fervently that they construct it - is the "Long Baseline Orbital Telescope." By placing a pair of imaging systems (each with better resolution than the Hubble) into two different locations - on opposite sides of the Earth - we would be able to combine the images and resolve objects of a fraction of an arcsecond. Exciting times ahead!

 

[vogon13]

Recall, a gas giant planet like twice as massive as Jupiter will still have a Hill Sphere well outside it's atmosphere, so atmospheric retention is possible for long periods of time.

Just don't buy real estate unless it's on the terminator.

 

[Shadowslayer81]

Thanks for the response! I did do some research into the different methods of detecting exoplanets and it makes more since now.

Definitely looking forward to the time when we get some awesome imaging telescopes in space to get more info and pictures of these planets. Too bad the sim planetquest mission is stuck in lack of funding hell. I guess I'm just used to being a bit skeptical about some things. Kinda like when your watching something on dinosaurs and they find half a skeleton of something then they cue to the CGI of what they think it looks like and then start talking about its mating habits how it feeds its young like they were standing there watching. Not that paleontologist do a bad job I just think people can get excited from time to time, and documentaries make it worse. Must be why i like astronomy and physics better, after all its more direct

Anyway I'll have to find some good resources on it and read about it more.

 

[dingo1]

I too am looking forward to the next generation of spaced based telescopes.

The problems I see with the indirect method, besides the obvious of finding an earth-sized planet, is the time that we are able to detect large Jovian sized planets that have a shorter orbital timeframe, vs a long period orbit, say in the magnitude of 100+ years. This issue I see with the indirect method is the quality of the older images and atmospheric distortion inherent with the older images. The short-period orbits of most of the planets found so far is due to the wobble is easier to detect. I figure most of the stars we have looked at and did not find any evidence, will need to be revisited when the new telescopes come online. I suspect we will start finding a lot of planets missed that are closer to earth sized around several of them.

 

[kg]

...The problems I see with the indirect method, besides the obvious of finding an earth-sized planet, is the time that we are able to detect large Jovian sized planets that have a shorter orbital timeframe, vs a long period orbit, say in the magnitude of 100+ years....

It's funny to think of having to wait decades for results. The anchent Babylonians and Chinese spent centuries developing techniques for predicting the motions of planets. It's good to take the long view of things.