I just read about this on an article on a danish site by the most famous danish astronomer these days, Michael Linden-Vørnle. I searched a little around here on BAUT and saw your quoting. Can you, or anyone else, provide me (us) with more imformation on this? I know information about unconfirmed discoveries are little, but i'm so thrilled about it i wouldn't mind reading about something that i would later find out isn't true

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After.

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Yep, that makes sense.

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"(sinc)" - spelling is not correct (in its orginal form) :)

I only repeated what I read in the ESA press release. It was quite surprising to read something so significant that seemed so unsubstantiated.

All I looked at about it on the web, are links back to the same ESA release.

Maybe someone else knows more about it. Or, we wait...

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Didn't even read the ESA press release, so thx for the link. But hard to wait when it is such an exciting subject. Unfortunately they haven't got any more info on this planet.

How long can we expect it takes from the first observations of an exoplanet until it is confirmed?

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George,

So, that subset must be equal to around 150 stars? Since 45/150 X 100= 30%. But it said in Greg Laughlin's post that 400 stars were non-active FGK type stars. Why then, if they are non-active, were 250 stars excluded from analysis?

In the article it says that 10% of sun-like stars have hot-Jupiters (jovians closer to their stars than Mercury is to the Sun), but only 1% have planets of this size and orbital separation.

I can't help but think that something is wrong with the information presented in this article...

I read it as the 30% includes two planetary populations: SuperEarths and hot Neptunes. They say...

"The notion that 30 percent of all sunlike stars have close-in superEarths or superNeptunes is “really remarkable."

The 45 only applies to the number of SuperEarths of the 400 stars in the study.

When you add the additional 10% for the third Jupiter class of planets to the 30% for the other two, we get 40% for all three classes. Thus, 40% of all sun-like stars have planets. I assume this percentage will be higher once the Earth-sized planets are detectable. Perhaps more than half of the F, G, and K class stars will be discovered to have planets.

The articles are little unclear of these numbers, admittedly. But I think I'm right. It would have been nicer to break it down as follows:

Of the 400 sun-like stars, at least...

11% have SuperEarths planets
19% have Neptune class planets
10% have Jupiter class planets

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"The mean of five measures each of which is not worth a dang (sinc), has a maximum value of only five dangs (sinc)". Heber Curtis

"(sinc)" - spelling is not correct (in its orginal form) :)

Some recent discoveries:

• MOA-2007-BLG-192Lb, as already discussed on this forum, marks the discovery of the first planet less massive than the two massive terrestrials around the pulsar PSR 1257+12. The third planet, PSR 1257+12 A (discovered in 1994, before 51 Pegasi b!) has a mass comparable that of the Moon and remains as the by far smallest known extrasolar planet, a title it has held for almost one and half decades despite misleading PR releases.
• The orange giant HD 102272 has a planetary system consisting of two massive Jovians. The outer planet orbits in a very eccentric orbit.

The discovery of MOA-2007-BLG-192Lb is remarkable in two ways: firstly, it suggests that terrestrials may form around the smallest stars and brown dwarfs, and that such planets may be very common. Secondly, our ability to detect that small deviations in gravitational lensing curves implies that the first true extrasolar Earth analogs will be found rather soon. Indeed, there are already rumors of such detections although they're not yet confirmed. But it does seem that terrestrial planets are very common also around more "normal" stars.

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Five super-Earths around three stars, courtesy of HARPS:

• HD 40307 (K dwarf) has a system of three super-Earths. HD 40307 b has a mass of mere 4.2 Earths so it is the smallest planet found by the radial velocity method so far.
• HD 181433 (K giant) has a closely-orbiting super-Earth and a much more distant gas giant.
• HD 47186 (late G dwarf) has a somewhat similar system.

Since the super-Earths orbit close to their stars (in the case of HD 40307 the orbital period of the outermost planet is 20.45 days!), and the stars are not red dwarfs they are by far too hot to be habitable.

According to the Extrasolar Planets Encyclopaedia, the total number of planet candidates is now 303.

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300+ and climbing.

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Lighten up! This is a stellar board! Author: duh.

"The mean of five measures each of which is not worth a dang (sinc), has a maximum value of only five dangs (sinc)". Heber Curtis

"(sinc)" - spelling is not correct (in its orginal form) :)

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
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According to the Universe Today article about the star with three super-earths in orbit around it, it appears that those orbits are pretty circular. I wonder if there's still the possibility of a more earth-like planet lurking in a more earth-like orbit around that star.

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It is quite likely that these planets didn't form in their current positions. Although it looks likely that terrestrial planets can form after the migration of a gas giant, the situation may be different in the case of (super-)terrestrial planets which form later. But there's certainly room left for habitable planets. Unfortunately, detecting an Earth-sized planet in the star's habitable zone is very difficult.

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More from the systemic blog:

As it was told earlier, the announced planets are only a tip of the iceberg...

With that number of super-Earth/Neptune candidates, odds for the discovery of a new transiting planet is almost certain.

This should be enough to detect our planet... too bad true solar analogs are probably too noisy spectrally. That's why super-Earth systems are mostly being found around orange and red dwarfs instead of Sun-like G stars.

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You mean "... from another star"? This really is exciting.

I will repeat a former question of mine i didn't get an answer to, but i expect that so,eone knows:

"How long can we expect it takes from the first observations of an exoplanet until it is confirmed?"

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Has anyone read the NYTimes article discussing the discovery of these super-Earths? The article was written by Denis Overbye and is called "A Bounty of Midsize Planets Is Reported."

In this article the American team led by Geoff Marcy issued the following statement regarding the Swiss team's finding (Overbye described the statement as "terse"):

"Our survey will check the Swiss report that 30 percent of stars have super-Earths or Neptunes orbiting closer than Mercury does the Sun...”

Now, obviously the wording is ambiguous, but notice what the American team did not say. They did not say something like "although our study is not yet complete, we can say that our preliminary data roughly corroborate the Swiss finding..." So, I wonder if the American team, whose results will be published in a year or two, are in conflict with the result just reported that "30 percent of stars have Super-Earths." To my knowledge, the conclusions reached by these two radial velocity searches have been roughly equivalent up until this point so a significant discrepancy may call into question the robustness of high precision radial velocity searches for extrasolar planets.

Or, perhaps Marcy et al will publish results which are consistent with these new results. Or, perhaps Marcy et al were just slightly miffed that they were not the first to find so many super-Earths.

Has anyone heard anything about a discrepancy looming between the results reached by the American team and the new results from the Swiss team other than what is hinted at in the NYTimes article?

I meant a planet like ours around a Sun-like star. Same thing.

Time? Preferably a full orbital period so that the orbit can be determined definitely. Number of data points? Depends on the signal. A hot Jupiter should be detectable using only relatively few data points, a smaller planet needs more. So a hot Jupiter signal should be clear in only a few weeks (few orbits). According to Greg Laughlin, a super-Earth needs about 25 times as many as data points as a gas giant. Which means it takes a much longer time to confirm a super-Earth than a jovian planet.

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Unless I'm mistaken, they don't have an instrument as accurate as HARPS. But on the other hand, they too have found some super-Earths so we shall see.

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It is too bad that a shadow of doubt has been cast over the stunning result that 1 in 3 stars have mid-sized planets around them. However, as someone on this forum has taught me, even if I think he is wrong in many of his radical assertions, the desire for a consensus should not result in our abandoning critical thinking.

There is something that I did not think of until just now: Greg Laughlin, he is part of the Marcy et al planet-finding team, right? And on a website that a link was provided for in this thread Laughlin did not hint that his team would dispute the result Swiss results nor did he anywhere in his statement express the kind of hinted-skepticism that the quote in NYTimes article arguably conveyed.

Yes, Marcy et al has found super-Earths, therefore, they must have a precision on par with that of HARPS. However, HARPS has been observing for a few years now, so I guess a logical question would be: Has the Marcy et al Super-Earth hunt, even if it is roughly as precise as HARPS, been observing its sample of stars for approximately the same period of time as HARPS observed the stars it did to come up with the recent Super-earth result? Is their stellar sample different in some respect (other than a slight difference in galactic location) that could explain a significant discrepancy in the frequency of super-Earths obtained?

If in fact there is a significant discrepancy even though the stellar populations are similar, then it is statistically unlikely that the differing fraction of super-earths just so happens to be so because the stars observed are in a slightly different part of the galactic disk. Plus, as I said in a previous post, the two teams have thus far sported similar results for Jovian planets. If they have instruments of roughly equal RV precision which they have used to observe a similar sample of stars for approximately the same period of time, then what physical process could lead to there being a significant discrepancy? Whose results should we believe, and perhaps more importantly, what implications would a significant discrepancy have for the epistemological soundness of RV-based planet-sluething in general?

OK, i think i understood you right the first time. You just wrote "This should be enough to detect our planet...", but you didn't say "...from another star". But yes, i understand your point that it (theoretically) should be possible to find a planet like Earth in another solar system.

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Why are you asking me? Find it out for yourself: go to ADS

http://adsabs.harvard.edu/abstract_service.html

and get all the recent papers by Marcy et al. by typing "Marcy" into the "Authors" box and pressing the "Send Query" button. Look at the resulting list, and pay special attention to

http://adsabs.harvard.edu/abs/2008PASP..120..531C

Then, replace the name "Marcy" with the name "Mayor". Again, look at the resulting list of papers, and scan those with names like, oh, this one:

"Pushing Down the Limits of the Radial Velocity Technique"

Voila! You will be able to answer your own questions!

Yeah, only $25 USD! What a deal!!!

I was under the impression that this a forum in which people ask questions, exchange ideas, and debate. I am merely throwing out a question in hopes that one or more of the thousands of people who subscribe to BAUT has some sort of answer; I am certainly NOT singling out a specific person to go out and find the answer. Given the vast number of astronomy enthusiasists contributing to BAUT (some of whom I suspect may be professional astronomers) I do not think it is an unreasonable assumption on my part to suspect that at least a few people might have an answer to this pertinent question on hand. As for answering my own question, I did search the astrophysics preprint archive using Marcy as the author name and that is where I found out (from reading papers) that the two RV searches teams have thus sported results that are in agreement with one another.

StupendousMan, have you read the aformentioned $25 report? If so, would you please share with us how it relates to my question so that all of the people following this thread do not have to make an unneccessary purchase? If you have not read it, then how do you know it will answer my question regarding a possible "Super-Earth discrepancy"?

Basically all I am asking is this: A groundbreaking result was announced along with a hint that it may be in dispute, and so, has anyone else who has been closely following extrasolar planet science of late found any evidence, other than the hinted-skepticism in the NYTimes article, that these two prestigious groups are not seeing eye to vis-a-vis this historic result?

So this would mean that in order to confirm a Earth-sized terrestrial in the habitable zone, it could take a year for a planet which orbits a similar star to the Sun?

I doubt that any team will be willing to keep such a groundbreaking find under their hats for that long.

So, the one article I mentioned in my previous post,
chosen by its title from Mayor's recent publications,
costs $25 to read online. Whoops. Sorry about that,
I didn't notice.

I used Google to search for more information about
HARPS, the high-resolution spectrograph which is
used at the La Silla 3.6m telescope to search for
planets. The $25 article looked like a good place
to find information on this instrument's capabilities,
but there is a lot of free information on the ESO's
web pages. In particular, this page:

http://www.ls.eso.org/lasilla/sciops...ject.html#publ

and this article which is linked to it:

http://www.ls.eso.org/lasilla/sciops...rs/6269-25.pdf

describe how HARPS reaches a precision of about
1 m/s in individual radial velocity measurements, making
it the most sensitive tool for certain types of
searches for extrasolar planets.

If one reads this document, and one of the recent papers
from Marcy's group which I mentioned in my previous post,
then one can compare the capabilities of their instruments
for oneself. It might help one to judge the claims made by
the groups.

I am not sure what the RV precision is of the Lick Observatory planet search, but I am pretty sure it is not as good as the one at Keck which is less than the proposed RV precision of the so-called "Rocky Planet Finder telescope." All of the three searches just mentioned are run by the Marcy et al team. According to "~A 7.5 Earth-Mass Planet Orbiting the Nearby Star, GJ 876" (Marcy et al 2005), the Keck RV precision, which I believe to be state of the art for this team, is "At Keck we routinely otain Doppler precision of 3-5 ms^-1 for M-dwarfs...." Now, this is for M dwarfs which are more faint than G dwarves and thus have spectral lines that are harder to measure, I think. So, although I am not sure, I think if the precision for M dwarfs is 3-5 then for solar type stars it is probably better-- maybe approaching 1-2 which would be competitive with HARPS. Therefore, if what I said above is correct, then the American team would be in a position to challenge or at least, as the NYTimes article said, "check" the Swiss results.

Kullat Nunu,

How does the discovery of MOA-2007-BLG-192Lb suggest that such planets may be very common? In neither the astro-ph/ preprint nor any of the press releases touched on this aspect--that is, they never mentioned the discovery's implications for how common small terrestrial planets may be. I am not trying to be an annoying doubter here, it is more that I am just curious about what the discovery actually says regarding small planet frequency.

Good question. What is the total number of detected microlensing events? The number of high magnitude events? In how many of the mass of a lensing object in high magnitude cases have been in the low red dwarf/brown dwarf range?

I don't think that many. Despite that, we have already discovered one such planet. Odds are they must be common. Of course, all of this is still very uncertain.

That was based on pure speculation (Greg Laughlin of the systemic project is the source). Like I said, the fact that we already know some of them despite the scarcity of such events strongly suggest that this is the case. When the accuracy becomes good enough (AFAIK it already is) we should be able to find the first Earth-mass planets in Earth-like orbits.

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New discovery courtesy of HATNet project, HAT-P-9b, which is a fairly ordinary puffed-up hot Jupiter. Interestingly, the previous HATNet planet was HAT-P-7b.

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Which makes 8b either a dismissed candidate or a potential awaiting confirmation.

By the by, ever think you'd live to see yourself typing those words about a planet orbiting another star?

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