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Faulkner
2004-Feb-27, 06:41 AM
I believe there's well over 100 detected "extra-solar planets" now, and the figure's climbing all the time.

My question is, are we detecting them purely on the basis of "stellar wobble"...or can we actually glimpse these planets in "occult" transit across the face of their suns?

In other words, are we merely "guessing" that these planets exist?

errorist
2004-Feb-27, 03:35 PM
Not only do they know that they exist but they also know what some of them are composed of. Once they make larger scopes to gather more light the more we will see. It is possilble to make a scope three hundred yards in diameter in space.

Duane
2004-Feb-27, 03:37 PM
This link (http://www.ucolick.org/~vogt/ay2/links.htm) is to a page with a number of links to various planet search programs. Check out the one to NASA's road map, it has a ton of information on the techniques of planet hunting.

ebbixx
2004-Feb-28, 01:09 PM
Within the next decade there are supposed to be some instruments constructed that will be capable of direct observation. At present, all work on ESPs has been by inference, measurements of movements in nearby stars that imply the existence of orbitting non-stellar masses and so on. In other words, indirect methods.

I read something very recently on the forthcoming instruments. Will edit this post to include references if I get the chance.

Faulkner
2004-Feb-28, 09:48 PM
So we are, actually, "guessing"? Sure, it's an educated guess, but it's still just an inference. It's one thing to say "we believe these planets exist" and quite another to say "they're there!"...Don't you think?

NasaBoy
2004-Feb-29, 12:54 AM
Yeah, but I mean lets be realistic here. Don't you think the Universe is TOO big and developed to have just ONE solar system?

Planetwatcher
2004-Feb-29, 03:42 AM
My question is, are we detecting them purely on the basis of "stellar wobble"...or can we actually glimpse these planets in "occult" transit across the face of their suns?
I know that Hubble has observed at least one extra solar planet in transit across the face of it's parent star, and it seems to me that I've read of a couple others making a possible three transit.occurances.
After a quick search I found a link confirming two of them.

Planetquest (http://planetquest1.jpl.nasa.gov/atlas/atlas_search.cfm)

Planetwatcher
2004-Feb-29, 05:06 AM
I just ran accross another transit candidate published just days ago.

transit candidate (http://www.konkoly.hu/24/obs/transit.html)

Here is the press release, but it is in German.

new transit (http://actu.voila.fr/Depeche/depeche_science_040225162336.dkuwi2zm.html)

VanderL
2004-Feb-29, 09:41 PM
Here is the press release, but it is in German.

new transit

Languages isn't your forte, apparently (J/K ;)). It's in French and that's a pity, German would have been ok for me. The only thing I can decipher is that the orbital period is 1.56 days, and the distance only 0.02 AU!
These extrasolar planets really are bizarre, when we compare them to our solar system. It seems we are still the odd one out.
Cheers.

Matthew
2004-Feb-29, 10:49 PM
Apparently a lot of extrasolar planets spiral into their parent star, bringing them very close to the star, and eventually they fall into the star.

Duane
2004-Feb-29, 11:08 PM
Recently the atmosphere of an extrasolar planet was analyzed, and measured. Another planet(I think another, might have been the same one) was found to be evaporating. Seems to me you couldn't get these results if the planets weren't there. ;)

Planetwatcher
2004-Mar-01, 01:30 AM
Here is the press release, but it is in German.
Languages isn't your forte, apparently (J/K ). It's in French and that's a pity, German would have been ok for me
Sorry about that. I saw a couple words which looked like they said duetch which I understood to be German for the german language.
Also it seems that there is an abundence of astronomy related sites and some of the worlds currently most renown astronmers are German. So I jumped the gun.

I suppose if we wait a day or so we will get the news either through U.T. or Space Daily. I get both.

ebbixx
2004-Mar-01, 05:25 AM
Originally posted by Faulkner@Feb 28 2004, 09:48 PM
So we are, actually, "guessing"? Sure, it's an educated guess, but it's still just an inference. It's one thing to say "we believe these planets exist" and quite another to say "they're there!"...Don't you think?
Of course there's a difference. And if you read primary sources, rather than the generally sloppy journalism that purports to "tell us" about such findings, you will find that the researchers themselves are very cautious not to overstep this line. They give their inferences, the logic behind the inference, and usually a number of qualifying statements to hedge the inference against future findings that may invalidate their own.

The first alleged "extra-solar planet" was a super-massive body that at least some subsequent studies have argued was a brown dwarf companion or something of that ilk, rather than a planet.

The more data and direct observation we can make, the closer we may come to narrowing down the menagerie of suspected ESPs to a subset that cannot readily be explained away by any other conclusion.

That's largely the way this sort of science works anyway, by process of elimination. One finds a suspect ESP because it doesn't fit the profile of any other known objects that it might have been. And my sense is that many of the suspected ESPs that have come after that first one have, at least, been harder to explain away as other sorts of bodies.

ebbixx
2004-Mar-01, 05:40 AM
Originally posted by matthew@Feb 29 2004, 10:49 PM
Apparently a lot of extrasolar planets spiral into their parent star, bringing them very close to the star, and eventually they fall into the star.
Keep in mind that the "wierd" sorts of ESPs are the easiest ones to find. Fast and close orbit, and high mass result in major perturbations of their host star's motions, for instance. This is how some of the earliest candidates were identified, and most of those I've read of continue to fall into the more massive category (large as Jupiter or larger).

Likewise, a planet that evaporates, or falls into its companion star, tends to create an observable event (not necessarily direct observation of the planet, but spectroscopy data or other observations that are the keys to pointing out their existence, or former existence.

All of this, however, does not mean earth-like planets do not exist out there. We simply do not have the means to identify them (yet), if they exist. There are ongoing surveys that are attempting to work at the question another way, by identifying those relatively nearby stars that are of a type that would tend to have a fairly wide potentially habitable orbital band around them and are otherwise "hospitable" candidates as nurseries for Earth-like planets.

If I understand correctly, the hope is that -- as these newer instruments go online that are capable of blocking out the light from the star, but leaving observable reflections and other aspects of the star's orbital neighborhood open for observation and analysis -- with such instruments and a good census of the most likely candidates, a systematic search will eventually be possible that would have some hope of identifying planets more like those in our own solar system.

Faulkner
2004-Mar-01, 09:36 AM
Nice summation, Ebbixx. ;) I wasn't doubting the existence of these planets, just questioning the seemingly over-confidence with which we were being told they existed! But looks like they're beginning to image planetary transits across the star's disk etc. So it's losing its "indirectness" and getting a lot more "direct" now!

Have they looked at Alpha Centauri A yet, I wonder?

VanderL
2004-Mar-01, 04:07 PM
Apparently a lot of extrasolar planets spiral into their parent star, bringing them very close to the star, and eventually they fall into the star.

If that's true, there wouldn't be very many planets left to detect eventually. I haven't heard about the planets in our solar system circling towards the Sun, so either we are still he odd one out or we will be gone sometime in the future.
Cheers.

TwAgIssmuDe
2004-Mar-01, 07:42 PM
I don't think astronomers guess that there are planets around other stars, for ex. the wobbling method where the star is affected by the planets gravity which orbits it. It had to be proven before it was used on other star.
Our solarsystem gave them the proof they needed, jupiter and sarturn affect our sun buy making it wobble.
So I will rather say that exsolarplanets exist eventhough our telescopes can't see them directly.

Duane
2004-Mar-01, 10:56 PM
Regarding planets spiralling into their stars, one of the theories regarding hot jupiters is that the planet formed some distance out from their sun and then migrated in as a result of tidal and gravitational interactions with other forming(or formed) large planets, interactions with the proto-planetary disc, interactions with left over dust/gas in the dics, or a combination of some or all of these.

Hot jupiters tend to be easier to find than other planets because of their size and proximity to their host star. The most comman technique of interferometry (pardon my spelling :rolleyes: ) used by Marcy and Butler and others tends to locate this type of planet quickly because of the degree of tug it's nearness and orbital speed have on their host stars.

As the amount and period of time of observations grow, so too do the number of planets found. Our own Jupiter, for example, orbits the sun in about 12 years. In order for the interfermetry method to locate Jupiter we would want at least 3 and as many as 5 orbits to confirm it. That translates to between 36 and 60 years. As we have really only been using this method for about the last 25 or so years, planets with longer period orbits haven't been confirmed as yet.

While some stars probably do actually swallow planets that get too close, it also appears that a very close orbit can be relatively stable. Once the process that started the planet's migration is removed, the planet may settle into a stable orbit for many millions or billions of years.

Considering there are billions of stars in our galaxy alone, no doubt we will see some stars that have swallowed their planet(s). So, while "a lot" may do this, it is likely that a lot more don't.

In our solar system, there is no fear of this problem until the sun enters it's red giant stage. The planets in our solar system are in stable orbits that would last beyond the life of our sun.

zephyr46
2004-Mar-02, 04:51 AM
Have they looked at Alpha Centauri A yet, I wonder?
Faulkner; Solstation.com (http://www.solstation.com/orbits/ac-absys.htm), I'm not sure about A and B but there was a stir about a possible companion to C, Proxima (http://www.solstation.com/stars/alp-cent3.htm).

I was wondering about the Pulsar Planets. As far as I am aware, the first, accepted planets were found orbiting a pulsar, and there were three of them. one of which was much smaller than jupiter PSR 1257+12 (http://www.extrasolar.net/mainframes.html). And now there is suppose to be a comet as well???
2630 light years away???

Anyway. I have decided I would rather remain an optimist as far as these discoveries go. Untill I understand or see proof that I understand that they realy exist :blink:

ESPs were one of the main reasons that I returned to Astronomy, after being sported away from it when I was much younger. Go ESPs GO !!

I remember a recent story about a Wolf-Rayet companion, talk about toasted ESP :)

Detection of oxygen and carbon in the hydrodynamically escaping atmosphere of the extrasolar planet HD209458b (2 February 2004) (http://www2.iap.fr/exoplanetes/index_en.html)

Manchurian Taikonaut
2004-Mar-03, 05:35 PM
The most important thing is increasing the power of our detection system and the power of our telescopes.


The massive "Jupiter-like" planets might be too hostile and have much gravity that would stop life from growing on their worlds.

But what about their moons, these extra solar planets have moons? And if we can look at these moons, maybe we can find oceans, and water like that on Europa?

Tom2Mars
2004-Mar-03, 06:17 PM
Hey Devilmech! Speaking of hard to find extrasolar planets, did you get my message? --Tom2Mars

devilmech
2004-Mar-03, 06:42 PM
Originally posted by Tom2Mars@Mar 3 2004, 06:17 PM
Hey Devilmech! Speaking of hard to find extrasolar planets, did you get my message? --Tom2Mars
I believe I just replied to it

Manchurian Taikonaut
2004-Mar-08, 07:22 AM
the image of the real deal, an earth like planet?

http://home.cwru.edu/~sjr16/media/esol_TMR1C.jpg

hubble on a planet hunt spots a distant world
( great image taken by infra red telescope )

http://exn.ca/news/images/1998/05/28/19980528-filamentplanet.jpg

damienpaul
2004-Mar-08, 08:10 AM
Is there any more data available about this spot, this intriguing spot?

Manchurian Taikonaut
2004-Mar-08, 02:16 PM
the image was comes from the Tauris constellation, Chinese call him Bi. I think the bulk of evidence points to the small image being a failed dwarf star rather than a real planet. Otherwise I'm sure we would have heard more information about it.
Or maybe scientists that use hubble are still wondering?

:huh:

Duane
2004-Mar-08, 05:27 PM
Yes T.D. Hong, you are right that this object was found to be a background star that just happened to be placed in such a way that it appeared at first glance to be a planet that was ejected from the binary star at the top midddle of the image.

Later measurements confirmed it was not a planet. it is another case of the media making a big deal out of a preliminary report, then not clarifying the results of later findings that determined the intial report to be incorrect.

Susan Tereby, the astronomer who made the initial report, herself reported a few weeks later that measurements revealed the object was not a planet, and more likely supported the view that it was a background star. I haven't seen anything to suggest it was a brown dwarf, rather it's light appears to have been reddened by foreground dust.

See CNN's April 7th 2000 (http://www.cnn.com/2000/TECH/space/04/07/not.a.planet/) article for more.

Peter Canuck
2004-Mar-11, 04:42 AM
Originally posted by ebbixx@Feb 29 2004, 11:40 PM
[All of this, however, does not mean earth-like planets do not exist out there. We simply do not have the means to identify them (yet), if they exist.

Earthlike or not, many scientists believe they have enough evidence to say there are ESP's in spot A spot B and so on.

Since science is by its nature a cautious and analytical process, I am sure that scientists who made the jump to declaring 'PLANET HERE!!!' had to have more than just a hunch a fuzzy picture to look at.

No one would go out and say something for certain exists unless they were certain themselves. That would be like saying the dog ran after the cat because it smelled like kibble. Do we know the cat smelled like Kibble... If it did, is that why the dog ran after it? Ask the dog. Well its tough to get confirmation from the dog since it does't speak our language or perhaps understand the word Kibble. Thats where science starts to ask questions, and if the scientist is confident enough in the answers to the question, draw a conclusion.

On the ESP, more than one scientist has looked at data and pondered and come to the conclusion of ESP's. Some did it with less evidence than others.

zrice03
2004-Mar-12, 12:17 AM
I calculated that the Hubble can image a planet that is the same brightness as Earth that is within 20.5 light-years (from the Moon, Earth is magnitude -16.7, and apparent brightness is an inverse square relation of distance, figure it out yourself!) Unfortunately, HST doesn't have an occulting bar so the light from the star would totally swamp the detectors (hint, hint designers of NGST...)