Talk:HD 10180

If this can be expanded by another 250 characters it can be nominated for DYK Smartse (talk) 16:40, 25 August 2010 (UTC)

The News Say Today that HD10180-B Has Been Confirmed as the First Discovery of an Extrasolar Earth-sized Planet

This is in an article under "Scitech" on cbsnews.com

Scientists in the article that they have a near statistical certainty that the planet does exist. They size it at 1.4 Earth masses.

164.47.80.222 (talk) 19:33, 25 August 2010 (UTC)

98.6% probability, yep that is pretty damn near sure, though if the planet's orbit is as close to HD 10180 as their estimate says it is (0.02 AU), that "Earth-sized planet" isn't very earth like at all, in fact it's likely hot enough to make Venus seem like a freezer! It seems like that last neptune-sized planet might hold some promise though, 1.42 AU puts it at a good distance to have habitable moons.67.142.172.25 (talk) 00:51, 26 August 2010 (UTC)

Habitable moons are merely speculation at this time, and there are fairly good reasons to suspect they are impossible. The mass of a gas giant's satellite system appears to scale with the mass of the planet, with the satellite system having of the order of 10^-4 of the mass of the planet. This would suggest a Neptune-sized planet wouldn't have satellites much larger than our own moon, too small to be habitable. Icalanise (talk) 06:36, 26 August 2010 (UTC)

That's true, though there is the odd chance that a larger moon could exist. Our own moon for instance is probably unusually large in comparison with the planet it orbits, though I do realize that this happened due to extrordinary circumstances and is probably a very rare phenomenom. -- Darthdyas (talk) 22:49, 28 August 2010 (UTC)

Also the mechanism thought to be responsible for the formation of our moon (and probably also (134340) Pluto I Charon and other similar systems), i.e. a giant impact blasting large quantities of material into orbit, relies on the planet having a solid surface, something a Neptune-type planet doesn't have. Icalanise (talk) 15:52, 29 August 2010 (UTC)

Or what about when the Neptune-sized planet was still rocky with a bit of gas early in the system's formation?--Fiahstorm (talk) 18:05, 8 December 2011 (UTC)

Can this system have habitable moons?

The Earth size planet is too hot for carbon based life to exist. Can any of the neptune sized planet's have moons that are are about the size of our moon? Or the size of Earth? Or Mars? CJISBEAST (talk) 19:07, 27 August 2010 (UTC)

As a long-time SF buff, I'd suggest 2 things. One, don't limit to carbon-based, in a hi-temp (& possibly exotic) atmosphere. Silicon? (Sentenced to Prism, for instance.) Something else? (Iceworld, for instance.) Fluorine in stead of water? Two, in the same vein, "habitable" moons might not harbor any life like us, but they might be lizards, arthropods (Thranx, anyone?), or cetacea (dolphin or orca). Or something "not only stranger than we imagine, but stranger than we can imagine". TREKphiler ^{any time you're ready, Uhura} 23:27, 28 August 2010 (UTC)

Possibly, very unlikely though.--Fiahstorm (talk) 18:06, 8 December 2011 (UTC)

An 8th planet?

http://solar-flux.forumandco.com/extrasolar-news-and-discoveries-f2/hd-10180-61-planets-t713-15.htm

"From this analysis (Fig. 12), one can see that stable orbits are possible beyond 6 AU (outside the outermost planet’s orbit). More interestingly, stability appears to be also possible around 1 AU, which corresponds to orbital periods within 300 − 350 days, between the orbits of planets f and g, exactly at the habitable zone of HD10180. Among the already known planets, this is the only zone where additional planetary mass companions can survive. With the current HARPS precision of ∼1 ms−1, we estimate that any objectwith a minimummass M > 10 M⊕ would already be visible in the data. Since this does not seem to be the case, if we assume that a planet exists in this stable zone, it should be at most an Earth-sized object."

Should planet I be added to the table? —Preceding unsigned comment added by 91.154.13.253 (talk) 09:33, 29 August 2010 (UTC)

I don't think this should be added to the table. This is merely a confirmation of a stable zone in the system, which may or may not contain a planet. For example, in our solar system there is a stable region between the orbits of Mars and Jupiter, which doesn't contain a planet. No-one's actually claiming to have any detection of an object within this region, which contrasts with the other two unconfirmed planets for which there is evidence in the data, but the planetary interpretation is less certain. As an addendum, the "exactly at the habitable zone" claim is somewhat dubious in the light of the fact that in the same paper, the luminosity of the star is quoted as 1.49 times the solar luminosity, which means the habitable zone would be located somewhat further out. Icalanise (talk) 10:41, 29 August 2010 (UTC)

Very high certainty but unconfirmed

I knew that the probability that unconfirmed planets b and h would almost certainly exist, since HD 10180 b is 98.6% and h is 99.4% probabilities that these planets do exist. Those percentages were so high that it is almost regarded as confirmed. For these two planets, they had a valid parameters. I think the reason why these two planets were unconfirmed because the inner-planet's mass is so low and a low-mass planet orbiting at a great distance from the star that the star did not produce enough wobbles that the RV signals from those planet weren't strong enough to confirm the existence of these planet. Perhaps it may take as little as few months until these planets confirmed by taking more time studying the wobble of HD 10180 from other observatories. Comments? BlueEarth (talk | contribs) 01:43, 30 August 2010 (UTC)

The paper indicates that it is not entirely clear whether the 2222-day signal is from a planetary origin or to do with stellar activity. The period for planet b is strongly affected by aliasing. Remember the false alarm probabilities tell you whether or not the periodicity is actually there, not what is causing that periodicity. Icalanise (talk) 07:37, 30 August 2010 (UTC)

Habitable zone image

Credit: Visual Exoplanet Catalogue

I have removed this image from the article as being potentially misleading. The source website [1] does not appear to give any indication of what definitions of the habitable zone are being used or what assumptions are being made to compute the boundaries. Such information is essential when discussing the potential habitability of a given planetary system. Icalanise (talk) 21:40, 27 September 2010 (UTC)

The website in question indicates that it is an estimate based on spectral type and luminosity. Will indicated that after I revert Nhorning (talk) 09:37, 3 October 2010 (UTC)

Sorry, but that still doesn't tell me anything about what boundaries are chosen. For example, take a look at Kasting et al. (1993), a paper which is widely cited in discussions of planetary habitability. They give several different possible limits for the habitable zone given there, all of which vary with planetary gravity and stellar temperature. Another paper worth looking at is von Bloh et al. (2007), which contains computation of habitability for the super-Earths at Gliese 581 by modelling the planetary evolution. As you can see the habitable zone gets modified by factors such as planetary ocean fraction, stellar age and planetary mass. The source website for the HD 10180 image does not give any clue as to how they are definining the boundaries. Icalanise (talk) 15:54, 3 October 2010 (UTC)

Individual Pages

I there any particular reason that none of the planets have their own pages yet? If there're no objections I'll make them.44Dume (talk) 21:45, 8 October 2010 (UTC)

I guess no-one got round to it. Icalanise (talk) 23:17, 8 October 2010 (UTC)

"At least seven planets" ??

The lead makes the claim that the system has at least 7 planets, while the article suggests there could be 9, it clearly states that only 6 are confirmed. How can there be at least 7 when it is only speculation that there any more than six .... --EvenGreenerFish (talk) 00:12, 11 April 2012 (UTC)

Here is the latest paper on which the possible 9 planets are claimed, http://arxiv.org/abs/1204.1254 (click PDF to the right). In particular see "We revise the uncertainties of the previously reported six planets in the system, verify the existence of the seventh signal, and announce the detection of two additional statistically significant signals in the data." The seventh was suggested in the discovery paper on this system, but at the time it could not be verified, it would appear this paper claims strong enough evidence for it to be finally confirmed. ChiZeroOne (talk) 11:22, 11 April 2012 (UTC)

The "Planetary system" section only seems to confirm five of these. Regards, RJH (talk) 17:58, 11 April 2012 (UTC)

Yes, it just looks like hasn't been updated yet to read as an ongoing process. Originally 5 were confirmed with 6 and 7 being possibles. 6 was then confirmed and now apparently 7th with two more possibles. This being said EPE is still saying the 7th needs additional confirmation and since Wiki tends to rely on EPE maybe a note about that should be made? ChiZeroOne (talk) 20:40, 11 April 2012 (UTC)

Evidence does not equal proof. To be encyclopedic uit must be officially confirmed, not simply have "revised uncertainties" and verification must be undertaken by a third party. There is evidence of life on Mars that does not mean that there is confirmed life on Mars. The table of 9 planets should also explicitly list those that are unconfirmed--EvenGreenerFish (talk) 04:09, 12 April 2012 (UTC)

As a physics graduate I think I fully understand the scientific method thanks... There is no such thing as "officially confirmed", there is no body that decides when an exoplanet is or is not "confirmed" nor are there any detailed requirements, that is for the peer review process and competing scientific teams. This paper, having been accepted for publication in a journal, has been reviewed by an independent expert in the field who has not found significant fault with it, that's how science works. Science is not as clear-cut as you may feel. Indeed many a time something has been "confirmed" and then later evidence from another team contradicted that interpretation, see the story of the detection and subsequent nondetection of Gliese 581 g.

Science never provides proof, as it fundamentally can't, only ever enough evidence at any one time to sufficiently convince the greater scientific community that a particular phenomenon exists or not. ChiZeroOne (talk) 14:41, 12 April 2012 (UTC)

OK I have now listed b as confirmed and merged the info into one up-to-date table. My main issue with the "confirmation" is that it was using the same data and the same method. --EvenGreenerFish (talk) 21:24, 12 April 2012 (UTC)