Talk:Kepler-186f

Creation

Created talk page for Kepler-186f - Enjoy! :) Drbogdan (talk) 20:06, 17 April 2014 (UTC)

Kepler-186f or Kepler-186 f?

Should the article name be Kepler-186f without a space - or - Kepler-186 f - with a space? - seems the original NASA and Science (journal) text prefers the Kepler-186f name - without the space - in any case - Enjoy! :) Drbogdan (talk) 20:10, 17 April 2014 (UTC)

After I redirected Kepler-186 f space to Kepler-186f no-space, you accidentally redirected Kepler-186f to itself, so I undid that. I agree no-space is in-line with NASA source. The title with space was created because the PHL website made the announcement before the press conference which was a few minutes late in getting started, and the PHL website used a space. Sorry for any mix-up. Astredita (talk) 20:18, 17 April 2014 (UTC)

@Astredita - Thank You *very much* for your comments - and sorting things out - no problem whatsoever - Thanks again - and - Enjoy! :) Drbogdan (talk) 20:27, 17 April 2014 (UTC)

Remove artists conception?

Can we remove the artists conception? No one has any ideas what it is made out of, much less what it looks like.--Nowa (talk) 23:14, 17 April 2014 (UTC)

FWIW - thanks for your comment - the NASA image (File:Kepler186f-ArtistConcept-20140417.jpg) seems ok to me atm - and is consistent with artistic images in other exoplanet articles (ie, Kepler-62f, Kepler-69c and related) - also, the present image seems to make the Kepler-186f article look better imo - of course, a real image of an exoplanet (or, at least, location tracks?, like the ones of Fomalhaut b on the Fomalhaut article for example) would be preferred of course - but the present image may be ok until then I would think - in any case - thanks again for your comment - and - Enjoy! :) Drbogdan (talk) 23:34, 17 April 2014 (UTC)

Agree, artists conception can go in the article, but the infobox should contain a generic ball/size comparison with the Earth and not an artists depiction.--EvenGreenerFish (talk) 00:20, 18 April 2014 (UTC)

1) This is allowable if properly labeled. The thing to do is to make it clear in the caption that it's an "artists conception".

2) Artist's conceptions also show the "popular media" phenomenon that occurs in reaction to some astronomy discoveries--

That in itself becomes a story and a subtopic. One could also call it "Kepler 186f in the media" or "Kepler 186f in popular culture". However again, it needs to still be made clear that it's an artists conception.

3) For balance, adding real science images is a good idea too (even a faint picture of the parent star, since we can't photo-image the actual planet). Or maybe a photo of the Kepler telescope (pre-launch of course), or a photo of the constellation Cygnus, "the part of the sky where Kepler1 86f was discovered".

4) It's also a good idea to keep in mind that Wikipedia is an encyclopedia for the general public, and is not a science journal.

I was curious about this. Who is the audience of this article? I changed some wording in the Mass, density and composition section to read more easily, but was reverted. (Example - changing "derivable" to "determined") Can the general public understand that section? Kaitymh (talk) 00:46, 1 May 2014 (UTC)

The edit wasn't reverted because of that choice of word - it was reverted because the rest of the edit changed the meaning of the sentence. The mass is not derivable/determined from the radius. Before your edit it was originally ambiguously written in way that could be read to give different meanings: it was meant to be interpreted as Its mass can only be derived from (the radius estimate+reasonable values for the density derived from assumptions of possible planetary composition). Not as (Its mass can only be derived from the radius estimate) and (reasonable values for the density derived from assumptions of possible planetary composition;) And in fact its mass cannot be derivable/determined at all: there is a wide range of possible masses it could have depending on different possible compositions. That's why I rewrote it to say: "Its mass is unknown but a range of possible masses can be derived by combining the radius estimate with a range of possible densities derived from assumptions of possible planetary composition". It has since been rewritten again to falsely give an impression that there is a single mass estimate. I will edit this to say "wide range of mass estimates". And given this wide range, I think the word 'determined' is misleading. Astredita (talk) 05:37, 1 May 2014 (UTC)

Thanks for the response @Astredita. I apologize, I didn't intend to change the meaning, I'm glad you caught it! Though I still think that this section too technical for most readers to understand. Could we provide a simpler language? Kaitymh (talk) 21:45, 2 May 2014 (UTC)

2602:306:BDA0:97A0:466D:57FF:FE90:AC45 (talk) 00:39, 18 April 2014 (UTC)

I understand, but there is a lot of misconceptions about what has actually been observed. The only thing we have "seen" is the dimming of the star when the planet transits it.

We don't know what it's made of or how massive it is. Somehow I think that needs to be made clearer in the article.--Nowa (talk) 09:10, 18 April 2014 (UTC)

That makes sense-- I would add the perspective you are sharing in the article (with proper citations). You are technically informed and so the right person to make those additions. Such a contribution will balance the article and make sure that the focus is not only on media perceptions / interpretations. Cliffswallow-vaulting (talk) 01:36, 19 April 2014 (UTC)

See Gliese 581 e or even Gliese 581 d ... this is how it should be done with an artists depiction in the body - not the infobox. The artist depiction is completely misleading, even when labeled. I mean, search for it on Google images and this is the first thing that will come up without any of the context. I would love it if something like the infobox graphic on Gliese 581e

could be made dynamic so that the circles could be configured by Wikipedians as more accurate figures are obtained. --EvenGreenerFish (talk) 12:28, 19 April 2014 (UTC)

I am not disagreeing with you in principle (does the artists concept image have to be in the infobox-- no, it doesn't). But please also don't drain the life out of the article in your zeal for scientific perfection. Wikipedia does allow artists concepts and they exist for a reason. This is an encyclopedia and not a science journal. It's for the general public, not hard-core scientists.2602:306:BDA0:97A0:466D:57FF:FE90:AC45 (talk) 18:56, 19 April 2014 (UTC)

I thought people might be interested in the background of the image - how much of it is based on what scientific views and so on - see [1]. --Smkolins (talk) 14:24, 28 April 2014 (UTC)

Is Kepler-186 a Flare star?

Is this a known flare star? How might this impact possibilities for life there?

2602:306:BDA0:97A0:466D:57FF:FE90:AC45 (talk) 01:21, 18 April 2014 (UTC)

I've added a ref which discusses flares. Also a link to Habitability of red dwarf systems.

It's been deleted from the article as too speculative but it said: "Red dwarf stars produce frequent flares and strong winds of radiation, so if the planet has a magnetic field it may have spectacular aurorae." http://www.newscientist.com/article/dn25444-smallest-lifefriendly-exoplanet-may-be-lit-by-auroras.html Astredita (talk) 15:30, 18 April 2014 (UTC)

Source

• http://www.huffingtonpost.com/2014/04/17/earth-like-planet-hosting-life_n_5168843.html?utm_hp_ref=tw

--Another Believer _(Talk) 01:34, 18 April 2014 (UTC)

HuffingtonPost reference is a duplicate of the AP News reference that's already cited in the main article - thanks in any regards - Enjoy! :) Drbogdan (talk) 02:04, 18 April 2014 (UTC)

Thanks. Just wanted to share in case it helped! --Another Believer _(Talk) 15:37, 18 April 2014 (UTC)

Sorry I didn't catch that! Maybe it would add credibility to the citations though, as it adds an additional credible news outlet possibly doing fact-checking on the same source. However I'm not really attached.I don't see any harm, but I also don't care if the citations are removed.Cliffswallow-vaulting (talk) 01:45, 19 April 2014 (UTC)

Temperature on the planet

Does anybody have an information about the approximate temperature on Kepler-186f? Also, does it have a Magnetic field? Also the "Artist concept" (drawing) of this planet does not seem quite right, because planets 1,5x of the size of Earth attract more gases like Helium and Hydrogen and rather look like Jupiter with very dense atmosphere. Life on this planet is rather a rarity or it does not exist at all.

— Preceding unsigned comment added by 164.8.33.30 (talk • contribs) 07:20, 18 April 2014‎ (UTC)

Kepler-186f is not 1.5x Earth's size, but 1.1x Earth's size [2]; so it's very likely to be terrestrial without a H/He atmosphere. It receives less energy from its star than Mars, so it's likely to be at least as cold than Mars unless it has a dense greenhouse gas atmosphere. Any magnetic field it may have is impossible to determine from the distance AFAIK. --Roentgenium111 (talk) 14:48, 18 April 2014 (UTC)

Is there any technology on the horizon that might be able to eventually analyze the limb of it's atmosphere as was done recently with one or two exo-gas giants? Cliffswallow-vaulting (talk) 01:47, 19 April 2014 (UTC)

Yes. I think there exists new technology already.http://www.news.leiden.edu/news-2013/new-telescope-may-be-able-to-detect-extraterrestrial-life.html Regards to the "Magnetic field" exploration on Extraterrestrial planets. We COULD detect Magnetic fields through the Sun(Star) particles around extraterrestrial planets if we could indirectly see the planet; especially over Starry wind, radio waves...Here is a little hint, source: http://curiosity.discovery.com/question/detect-magnetic-fields-exoplanets — Preceding unsigned comment added by 149.126.157.96 (talk) 21:46, 19 April 2014 (UTC)

metallicity

Is it too strong to say that if the star is clearly lower metallicity that the overall metallicity of the system should be low and thus tend to suggest F isn't likely to be higher than Earth in metals? I know the rocky planets vary but the inner planets seem to have more of the iron than the outer planets. Does anyone know a cite for that pattern? I suppose OR arguments would have to be carefully avoided… --Smkolins (talk) 15:08, 18 April 2014 (UTC)

[3] is kind of in the same direction as I'm trying to clarify… --Smkolins (talk) 15:11, 18 April 2014 (UTC)

When system forms the radiation from star means volatile substances such as water, ammonia evaporate so are found further away in the outer regions of the system. Substances which are the opposite of volatile, Refractory (planetary science) substances such as iron, calcium, aluminum don't evaporate so easily and so are found in abundance nearer the star. Silicon and magnesium which are the major constituents of rock are intermediate and are mostly found at intermediate distances.

Once large enough amounts of a substance clump together into planetessimals then these can be scattered throughout the system by gravity which means water which condenses into ice further out than the HZ can be delivered to the habitable zone by comets/asteroids. So gravity scatterring mixes up the volatile and refractory elements somewhat. Astredita (talk) 15:23, 18 April 2014 (UTC)

Right on both such ideas from my understanding as well - and I also know the planets can switch places after the system is made… here's an interesting point: low metaliccities enhance the likelihood of Earth-like planets (fourth slide) --Smkolins (talk) 15:31, 18 April 2014 (UTC)

btw here's a site for the point you made - there may be better but just ran across it - Muriel Gargaud; Purificación López-Garcìa; Hervé Martin (6 January 2011). Origins and Evolution of Life: An Astrobiological Perspective. Cambridge University Press. p. 139. ISBN 978-1-139-49459-5. --Smkolins (talk) 15:38, 18 April 2014 (UTC)

here's one arguing a metallicity minimum for likihood for life - [4] --Smkolins (talk) 15:41, 18 April 2014 (UTC)

a review of the history of metallicity investigations in planet formation [5] but again nothing about whether the planets themselves are more or less likely to have metals and in what concentrations. Unless someone else can find something looks like it is a bit of a blind alley on this angle. --Smkolins (talk) 17:23, 18 April 2014 (UTC)

Lack of Finding is not Encyclopedic

In science and exploration there are many failures, sometimes thousands or millions. Not every failure of every scientific project is significant.

Some editors here, trying to make a plug for one particular science project that has NEVER produced any results, are suggesting that a failure is significant to the article topic. It isn't. There are any number of scientific projects that have looked at the Moon, for example, and utterly failed. Lack of positive results in an experiment may suggest something significant, but in the case of SETI, it does not. No SETI project has ever found any signal that can be replicated.

The lack of results not only suggests that the hypothesis as a whole is incorrect, but that the equipment itself is deficient. Neither situation is remarkable in any scientific way.

This is an encyclopedia for facts, not non-facts. 24.6.156.141 (talk) 16:09, 18 April 2014 (UTC)

I disagree - the scientists themselves went through the effort of requesting a survey by the Alan observatory. They published the investigation. That makes it salient. --Smkolins (talk) 16:20, 18 April 2014 (UTC)

I disagree as well, lack of findings can of course be a relevant piece of information. No one here is trying to make a "plug" for anything, please read WP:FOC and WP:AGF.

Given the relevance of this particular object, explicitly mentioning that SETI already studied it, for how long and how strong the signal should be are all encyclopedic bits of reliably sourced information. Furthermore this "The lack of results not only suggests that the hypothesis as a whole is incorrect, but that the equipment itself is deficient", is you own WP:OR and as such has no weight whatsoever. Let's wait what other editors have to say and please do not continue reverting to remove content from the article. Regards. Gaba ^(talk) 16:21, 18 April 2014 (UTC)

Smkolins and Gaba , from just what you've written, I doubt either of you have worked on a SETI project. Requesting an observation is a routine astronomical activity, and Wikipedia cannot be a record of every observation, successful or unsuccessful.

There's no "original research" implied by stating that the SETI equipment on any given project could have failed. When a typical SETI observation fails, the result is simply static. There's no "litmus test" about whether the static is correct. Equally, malfunctioning or poorly adjusted equipment can produce random noise. Noise can (and does) come from background noise and habitual equipment noise. So a negative SETI observation proves exactly nothing. Please don't bother to contradict me, I know SETI scientists, I have seen the process, and I have heard their rational. My opinion about that may be inadmissible Wikipedia evidence, but I assure you, you will not be able to find a SETI scientist who says much of anything different. Noise is just noise. It does not necessarily mean that a valid experiment has been performed. 24.6.156.141 (talk) 16:43, 18 April 2014 (UTC)

Aside from not needing to characterize other editors and blowing opinions to the winds the scientists DIDN'T request doppler examinations of the star for the planets and DID request Seti investigations. --Smkolins (talk) 16:50, 18 April 2014 (UTC)

Smkolins, you're really turning Wikipedia on its head here. Do you see that? There has been a SETI survey of the entire sky. (JPL's Sky Survey, for example.) By the reasoning you gave, every Wikipedia article on a star should include a sentence: "No radio signals suggesting intelligent life were discovered at this star." 24.6.156.141 (talk) 16:59, 18 April 2014 (UTC)

No I'm not. If I did that it would be OR by me. Do you see the difference? for another example I'm not aware anyone is trying to argue a general lack of intelligent life in the universe from this or any combination of such lack of evidence. That too would be OR (until someone publishes an article in a journal long those lines and I'm not aware anyone has.) --Smkolins (talk) 17:06, 18 April 2014 (UTC)

I can understand the opposition in general to including information about the lack of any signal in articles on stars. However in the case of this article, as the first Earth-sized planet in a habitable zone, a SETI search result of any kind is worth including. Astredita (talk) 17:05, 18 April 2014 (UTC)

alternative older name KOI-571-05

I'm finding some mention of this name (or KOI-571.05) back into 2013 in various discussions…. [6], [7], [8] Not exactly sure how to frame this but someone might. --Smkolins (talk) 16:45, 18 April 2014 (UTC)

related in the sense of previous mention, a fifth non-hypothetical planet for KOI571 is listed in here • [9], look for KOI-571. There are two graphs and the key at the bottom indicates it's not one of the hypothetical planets and it was published in 2013. --Smkolins (talk) 16:53, 18 April 2014 (UTC)

btw I finally figured out "KOI" is Kepler Object of Interest. --Smkolins (talk) 17:36, 18 April 2014 (UTC)

KOI-571.05 is a designation for a candidate planet, Kepler-186f is for one that's been validated. There's also a KIC number related to the star. -- 65.94.77.36 (talk) 04:40, 19 April 2014 (UTC)

"Orbital parameters relative to habitable zone"

Once again astronomers report finding the first ever earth-like planet in a habitable zone.

Why do they keep doing this.

If "habitable zone" means anything, then it does not mean "colder than Mars." Flabellina (talk) 19:58, 18 April 2014 (UTC)

If you are referring to Kepler-22b, it is much larger than the Earth (2.4x Earth radius) and is by all accounts probably a mini-gas giant or water world without potential to support advanced life. The currently discovered planet, however, has only 1.14 times Earth's gravity and radius and would be quite comfortable to walk on for humans and easily colonized by terrestrial life. For more information about the habitable zone please read Wikipedia's article on it. I personally wrote the majority of the current iteration and can vouch for its accuracy. Wer900 • talk 21:58, 18 April 2014 (UTC)

Tidal locking

I noticed that it is reported that the exoplanet has a "50-50 chance of being tidally locked" but that it shares an orbit similar to that of Mercury's. Wouldn't that mean that the planet couldn't be tidally locked, especially considering that the M-type star has a significantly smaller gravitational pull on the planet than on Mercury? exoplanetaryscience (talk) 22:21, 18 April 2014 (UTC)

If Mercury had a circular orbit it would be tidally locked. The eccentricity of Mercury's orbit allows it to avoid tidal locking. Kepler-186f has a circular orbit and so will evolve towards tidal locking. (see Tidal effects on rotation rate, axial tilt and orbit) 22:26, 18 April 2014 (UTC)

Actually, they haven't determined the planet's eccentricity yet. I also happened to notice that the planet has an inclination very close to a right angle to the plane of the star's movement, so wouldn't that make it take a longer time to be tidally-locked?. exoplanetaryscience (talk) 22:52, 18 April 2014 (UTC)

The inclination of exoplanets is usually stated relative to the line of sight to Earth. Therefore all transiting exoplanets have an inclination of 90degrees relative to the line of sight. (see Exoplanet#Inclination). Astredita (talk) 22:59, 18 April 2014 (UTC)

Thanks for that info. Can you happen to find anything talking about Kepler-186's rotation orientation? exoplanetaryscience (talk) 23:01, 18 April 2014 (UTC)

The SETI video in the links section mentions that the orbit is circular and that the rotation axis is not tilted. However the zero axial tilt is not something they can measure - in the video they just say they expect it to be straight up. Astredita (talk) 23:20, 18 April 2014 (UTC)

Well then, I don't see why the planet wouldn't be tidally locked. The page/section you sent me in the first reply mentions that the planet orbits further away the more its period is lengthened, which seems to fit its orbit just within Mercury. The planet orbits with no eccentricity around an M-dwarf, which has a fairly long time in the main-sequence, and therefore probably be older. Combine all of these together, and the planet's status is... inconclusive. I guess it all depends on finding the star's orbital orientation. By the way, you can find the axial tilt of the star by observing sunspots on it, which I'm sure the Kepler team would have access to. — Preceding unsigned comment added by Exoplanetaryscience (talk • contribs) 23:29, 18 April 2014 (UTC)

Mercury IS tidally locked, only in a 3:2 resonance instead of the more usual 1:1 resonance. --Roentgenium111 (talk) 16:49, 20 April 2014 (UTC)

Ok but the above discussion and the Tidal locking article use 'Tidal lock' to mean 1:1 Astredita (talk) 20:00, 20 April 2014 (UTC)

First ??

What about Kepler-62f ? Its radius is just 1.4 times Earth's. Is 0.3 Earth radius really that significant ? From what I've read, Kepler-62f planet is has a higher Earth SImilarity Index and orbits a K-class star, more similar to the Sun ... What happens when we find one with exactly 1.0 Earth radii ... won't that be the "first"? --EvenGreenerFish (talk) 12:24, 19 April 2014 (UTC)

It pretty much all depends on what you count as 'earth sized'- often planets with masses of ~3-10 times that of Earth begin to acquire a gaseous envelope and become gas giants, but nobody knows exactly what the boundary is, so some of the planets that have masses a few times that of Earth aren't necessarily counted because gas giants aren't really habitable.

FWIW - possible habitability of planets that are gaseous (and/or large) is discussed to some extent at Talk:Kepler-86#habitability re Kepler-86b (or PH2b) - as well as - < ref>http://adsabs.harvard.edu/abs/1976ApJS...32..737S</ref> - apparently, the biosphere (and/or biomass) of planet Earth may be mostly composed of microbes - many, maybe most, floating in at least 40 miles of atmosphere (< ref>http://www.answerbag.com/q_view/492401</ref>) - a layer of gases, of course - in any case - Enjoy! :) Drbogdan (talk) 14:16, 19 April 2014 (UTC)

Then there's the problem of gravity. Planets with masses 1.5-2 times Earth's mass are hard to walk on- the current gravity of Earth is about the maximum we can handle with our current bodies, and a planet larger than that would be deemed 'ununhabitable' or at least harder to inhabit.

I would say it is safe to say that pretty much any planet with a radius/mass between 0.8 & 1.2 Earths- that would be 'Earth-sized'. — Preceding unsigned comment added by 142.136.145.221 (talk) 13:22, 19 April 2014 (UTC)

I have to agree with EvenGreenerFisk - why is this planet/article more important than the many other planets discovered so far that are near "Earth-size"? The media hype on this planet has been very thick during the pasr 24 hours, being the front cover of my local newspaper in this article... Even claiming that: " "This is the best case for a habitable planet yet found. The results are absolutely rock solid," University of California, Berkeley astronomer Geoff Marcy, who had no role in the discovery, said in an email". Maybe they don't read Wikipedia? Geez - why don't they interview us? :( Dinkytown talk 13:30, 19 April 2014 (UTC)

The volume of a sphere

$\!V={\frac {4}{3}}\pi r^{3}$

so Earth-volume is 4.188 cubic-earth-radii and volume of a 1.1radiusplanet is 5.575 cubic-earth-radii or 1.331Earth-volumes and volume of a 1.4radiusplanet is 2.744Earth-volumes.

So a 1.1 is a bit more than Earth-volume but a 1.4 is nearly three times the volume and mass compresses so this volume could fit even more mass if the planet is rocky. Astredita (talk) 16:32, 19 April 2014 (UTC)

The paper Origin and Loss of nebula-captured hydrogen envelopes from "sub"- to "super-Earths" in the habitable zone of Sun-like stars says that planets with even a bit more mass than Earth could retain substantial hydrogen atmospheres and recommends 0.8–1.15Earth radii as the range that are small enough to lose their accreted Hydrogen envelope but large enough to retain an outgassed secondary atmosphere such as Earth's. Astredita (talk) 16:38, 19 April 2014 (UTC)

Age of the parent star

How old is the star estimated to be?2602:306:BDA0:97A0:466D:57FF:FE90:AC45 (talk) 19:30, 19 April 2014 (UTC)

The age is unknown but probably more than few billion years as described in the Formation, tidal evolution and habitability section. The paper says it could be less than one billion but is probably more. Astredita (talk) 20:10, 19 April 2014 (UTC)

Is Kepler-186f really habitable?

I was thinking about the planet's actual habitability around a red dwarf star, but then I realized- "what about the solar wind?"

Red dwarf stars are known to be fairly cool, which is why the habitable zone is in the 0.3AU region, but they're also known to have violent activity on their surface, presumably leading to nearby planets being baked in radiation.

Now back to the cool: the planet Mars, scientists say, could have maybe had a magnetic field once, but since cooled down too much for the field to remain active. Kepler-186 is definitely cooler than Earth, likely ranging ~20-40 degrees on average. The planet, of course, would have cooled down more rapidly than Earth, weakening, if not completely destroying its magnetic field, which is the only thing that keeps solar wind radiation out.

Without this magnetic field to stop it, the planet would receive enough radiation to kill a human on the planet with no protection in a matter of hours (not including other dangers.)

So I ask you this; is the planet really habitable? — Preceding unsigned comment added by 142.136.145.221 (talk) 13:33, 20 April 2014 (UTC)

• 1) the only variability noted for Kepler 186 is that of rotation (so far.)
• 2) I do see comments about red dwarfs also having relatively high UV either at the beginning or over time but so far that is associated more with blowing away the H-He early atmosphere.
• 3) I agree about more like Mars for basics but it is also much larger and perhaps more likely to have a significant atmosphere. So perhaps it's a bit warmer than Mars gets at night and alittle warmer in the daytime - but it may be basically glaciated if there is enough water around. --Smkolins (talk) 13:39, 20 April 2014 (UTC)

Earth Similarity Index

I have seen claims of 0.64 which would be less than Kepler-62F. Does anyone have a citation so that the figure could be added here for comparison. --EvenGreenerFish (talk) 12:39, 19 April 2014 (UTC)

I've known this place to add details on planets not typically included by other catalogs; it lists the habitable zone inner and outer boundaries, if the planet is within, closer, or further than that zone, and the open exoplanet catalog shows an orbit diagram, mass comparison, and temperature. However, since the planet has only been reported a couple of days ago, there isn't much 'new' data on either of them. 142.136.145.221 (talk) 13:17, 19 April 2014 (UTC)

The Habitable Exoplanets Catalog lists Kepler-186f as no.17 but List of potential habitable exoplanets which starts by saying it also uses the ESI lists Kepler-186f as no.40. Astredita (talk) 17:46, 19 April 2014 (UTC)

I removed the ESI text but my edit was reverted. I removed it because I don't think it relevant. The Earth-Similarity-Index is not a scientific metric. It is some made up stat that is not used in the published scientific literature. This page should be based on valid information on the planet. — Preceding unsigned comment added by Necron5555 (talk • contribs) 23:30, 19 April 2014 (UTC)

Thank you *very much* for your comment - yes, I reverted the edit - in order to give other editors an opportunity to comment before removing the section - for myself, I consider the sourced section of possible interest to usual viewers (perhaps somewhat non-technical?) based on the following => Readability of Wikipedia Articles (BEST? a score of 60/"6th grade/11yo" level) - but am flexible atm - Thanks again for your comments - and - Enjoy! :) Drbogdan (talk) 01:00, 20 April 2014 (UTC)

(source of ESI)[10], Calls it "proposed" with some criticisms [11], qualifies some usefulness [12], used somewhat [13], seems to be a new tentative scale. I've yet to see a serious criticism, just that it is a limited usefulness. I think it's ok to use it qualified as a proposed standard of comparison but leave the qualifications to its own article. --Smkolins (talk) 01:23, 20 April 2014 (UTC)

For most Kepler planets and planet candidates all we know are the radius and orbital period and some stellar parameters including luminosity. Nothing about atmosphere or what the planet is made of. The Earth Similarity Index used in the table can be used as a temporary preliminary measure for comparing planets until more information is available. Astredita (talk) 00:00, 21 April 2014 (UTC)

(Candidate Earth-size planets in the HZ of Sun-like stars)

So far this table has almost nothing to do with f. If more is not added it should be taken out. I'd have taken it out already but am siding on the idea that the f data will be added…. --Smkolins (talk) 20:23, 20 April 2014 (UTC)

More over a constructive use of the content would be to merge "Earth Similarity Index" and "Comparison with previously discovered low-mass planets in the HZ" with it, I'd say. --Smkolins (talk) 20:28, 20 April 2014 (UTC)

I've merged "Earth Similarity Index" with the Earth-size candidate table. Astredita (talk) 00:15, 21 April 2014 (UTC)

Earth Similarity Index is a misleading metric – Earth's position at the inner edge of the habitable zone means that planets outside the HZ close to the hot edge can get higher ESI values than planets within the HZ close to the cold edge (it also fails to account for the HZ moving to lower levels of insolation around cool stars due to albedo variations). I'd advocate removing the ESI-based table so as not to further promote this misguided approach to planetary habitability. 77.56.99.23 (talk) 22:21, 21 April 2014 (UTC)

The ESI could be removed from the table and the table would still be a list of candidate Earth-size planets in HZ of sun-like stars. Astredita (talk) 22:41, 21 April 2014 (UTC)

Why is listing candidate Earth-sized planet candidates relevant? When they are confirmed they become interesting but as candidates they are don't add anything. Listing a bunch of things that may well turn out to be (a) eclipsing binaries or (b) much larger planets orbiting giant stars or (c) instrumental noise artifacts just serves to confuse. This is the only Earth-sized planet in the habitable zone. Why are we attempting to downplay this? I don't think this subsection has a place. However, the 'Comparison with previously discovered low-mass planets in the habitable zone' section does serve an important role of placing this into context [although we don't know the mass of this planet]. Necron5555 (talk) 03:15, 22 April 2014 (UTC)

Agreeing in principle to the comment on the listing, maybe the table can be moved to a new section in Kepler Object of Interest. -- Karl432 (talk) 06:51, 22 April 2014 (UTC)

I think listing candidates is interesting. This isn't about downplaying the result but pointing to what else is in the Kepler data. They are candidates and there is a false-positive rate of about 10% for candidates, and even if they are confirmed the sizes could be revised upwards but the section clearly states they are candidates and not confirmed planets. Astredita (talk) 22:13, 24 April 2014 (UTC)

Is there any reliable source for choosing the current 5 other "candidate Earth-size planets in the HZ of Sun-like stars" among the hundreds of Kepler candidates and the dozens of HEC HZ candidates? The list seems to just be a copy of the referenced anonymous ("Ronald") user comment to the Centauri Dreams blog, which is obviously not a reliable source. The HEC list contains some "warm terrans" not listed here, while two of the listed candidates are not "terrans".--Roentgenium111 (talk) 21:08, 24 April 2014 (UTC)

The table is from the comment, but the data is originally from NASA's table or from NASA's individual pages for each candidate. e.g. http://exoplanetarchive.ipac.caltech.edu/cgi-bin/DisplayOverview/nph-DisplayOverview?objname=K05545.01&type=KEPLER_CANDIDATE The table is just those planets in NASA's table that are closest to Earth in size with HZ levels of luminosity. I don't think selecting such candidates is any more WP:OR than many other exoplanet lists such as List of exoplanet extremes and so it is not the use of the table that needs reliable sources but only each individual entry that needs sourced which they can be by linking to NASA's main table or to NASA's individual candidate pages. Astredita (talk) 22:12, 24 April 2014 (UTC)

So what are the supposed criteria for inclusion in the table? The table is NOT just "those planets in NASA's table that are closest to Earth in size with HZ levels of luminosity" - as I said, it does not list all seven HZ "terran" candidates in the HEC's list (which are those with a mass very close to Earth), but lists a "subterran" and a "superterran" planet each, whose assumed masses deviate more from Earth than the missing "terrans". The raw data is of course referenced, but the choice of candidates is OR unless we can give objective selection criteria. --Roentgenium111 (talk) 20:09, 27 April 2014 (UTC)

This page could be useful Calculation of Habitable Zone for the HZ distances. For Earth-size the HEC uses 0.8 to 1.25 Earth radii which is larger than the 0.8–1.15 from the Lammer paper mentioned in this article. Astredita (talk) 10:51, 28 April 2014 (UTC)

The HEC list seems to have a typo because it lists Venus as a warm-terran but lists it as a hot-terran in figure 3 of the Periodic Table of Exoplanets Astredita (talk) 11:01, 28 April 2014 (UTC)

I think we should go with the Lammer criteria for Earth-size as it is the most recent. The main thing is that the table should have a footnote or header that states the inclusion criteria. Astredita (talk) 11:04, 28 April 2014 (UTC)

Sounds good to me. --Smkolins (talk) 14:26, 28 April 2014 (UTC)

Thanks for pointing out Lammer's size range estimate. But he only gives the 0.8–1.15 mass range for G-star planets, which is not exactly what we are considering here. And the existing table is incompatible with both size ranges...

The different classifications for Venus are probably due to a mixing up of the actual and the assumed "albedo=0.3" equilibrium temperatures for Venus: Venus' given equilibrium temperature in the HEC list is smaller than Earth's. (But this mistake is rather irrelevant for the exoplanet list.) --Roentgenium111 (talk) 18:58, 29 April 2014 (UTC)

Going back to the start of this discussion, I fully agree that this table does not belong here. This is the Kepler-186f article, not list of potentially-habitable exoplanets or whatever. 77.57.25.250 (talk) 18:27, 29 April 2014 (UTC)

I have excised the table and its associated section from the article, the excised content is below. This is really not particularly relevant to Kepler-186f, and this is not the article to maintain such a list. 77.57.25.250 (talk) 08:57, 4 May 2014 (UTC)

I tend to agree this does not belong here. Perhaps as above or a daughter page or addition to List of exoplanets detected by timing.--Smkolins (talk) 12:56, 4 May 2014 (UTC)

I also agree with the removal. But the table shouldn't be added in another article either, as long as the choice of entries is pure OR. --Roentgenium111 (talk) 18:52, 6 May 2014 (UTC)

Candidate Earth-size planets in the habitable zone of Sun-like stars

Kepler-186f orbits a red dwarf but there are some Kepler candidate planets yet to be confirmed that could be Earth-size and orbiting in the habitable zones of Sun-like stars.

Table comparing Kepler-186f (KIC 8120608 = KOI-571.05) to candidate Earth-size HZ planets:

Kepler Input Catalog	Stellar Luminosity (LSun)	Stellar radius (RSun)	Metallicity (dex)	Kepler Object of Interest	Planet radius (REarth)	Planet semi-major axis (AU)	Orbital period (days)	Insolation (% of Earth's)
KIC 5091808	0.69	0.83	−0.82	KOI 5123.01	1.09	0.77	289	116%
KIC 11654039	1.09	0.97	−0.14	KOI 5927.01	1.24	1.13	436	85%
KIC 10663976	0.44	0.73	−0.46	KOI 5819.01	1.29	0.95	381	49%
KIC 11465869	0.53	0.74	−0.28	KOI 5904.01	0.77	0.86	323	72%
KIC 8570210	0.67	0.80	−0.42	KOI 5545.01	1.05	1.25	541	43%
KIC 8120608	0.04	0.47	−0.28	KOI-571.05	1.11	0.36	130	31%

Insolation is calculated by taking the luminosity and dividing it by the semimajor axis squared.

References

Target of SETI investigation

So we have two compatible statements from two seti orgs that tend towards different views (one says no positive evidence but the signal would have to be huge to be seen, the other says there may be some signal among the noise, its sketchy but noticeable by some, arguable, criteria.) So my mind turns to other seti projects like SETI@home. At first I wondered if it even covered the right part of the sky - apparently not [14]:"it can only cover about one third of the sky, and it can't see any of the earth-like planets that the Kepler mission found", but the project has had some extension thanks to the Green Bank Telescope perhaps in two stages: ([15], [16], [17]) and SERENDIP but all the references are older and am unsure they are in fact still running or looked at 186 since it is newer. I don't think there is a place with any posted data?? --Smkolins (talk) 01:33, 4 May 2014 (UTC)

Hmmm [18]. Close? Does /not/ include 186, aka 570, aka 8120608. --Smkolins (talk) 01:54, 4 May 2014 (UTC)

"So we have two compatible statements from two seti orgs that tend towards different views (one says no positive evidence but the signal would have to be huge to be seen"

That's why it is the work of "SETI" really useless. So which signal do they need, 2.2-gigawatt transmitter? — Preceding unsigned comment added by 164.8.33.30 (talk) 06:53, 3 June 2014 (UTC)

Habitability Utterly Phony

This is not for the article, it is for Editor's reference.
Anyone who can do the math can see that any habitability suggestions for this planet are utterly phony.
http://exoplanetarchive.ipac.caltech.edu/cgi-bin/TblView/nph-tblView?app=ExoTbls&config=planets

Host Name, Planet Letter
Kepler-186 ,f

Data Point	Values	Error ranges	(+/-) Maximums
Star Radius (sol)	0.523	0.023/-0.021	0.546
Effective Temperature (K)	3755	± 90	3845
Orbit Semi-Major Axis [AU]	0.432	+0.171-0.053
Orbital Period [days]	129.9441	+0.0013/-0.0012
Eccentricity	0.04	0.07/-0.04	0.11
Perihelion Flux (W/m^2)	160.714	11.76%	192.774	14.11%
Average Flux (W/m^2)	154.285	11.29%	171.569	12.56%
Aphelion Flux (W/m^2)	148.351	10.86%	154.566	11.31%
Solar Constant (W/m^2)	1366.078	100%	1412.91	103.43%

• ((((0.523*695500000)^2)*(0.0000000567051)*((3755)^4))/((0.432-(0.432*0.04))*149597870690^2))

• ((((0.546*695500000)^2)*(0.0000000567051)*((3845)^4))/((0.432-(0.432*0.11))*149597870690^2))

• ((((695500000)^2)*(0.0000000567051)*((5778)^4))/((1-(1*0))*149597870690^2))=1366.078 or 100%. Earth's Solar Constant.

24.79.36.94 (talk) 17:33, 15 February 2015 (UTC)

Incorrect Planetbox usage

The image in the infobox should not be used as it does not follow the usage guide for the template:

This template is part of a group of templates that are used to display information about a specific extrasolar planet.
Images of published planetary properties are preferred where available, especially when they are available from cited publications.
Artist's conception, regardless of the source, should be avoided.
Examples of acceptable images include
* direct images, such as one used for GJ 758 b, in the rare cases where these are available;
* output of a model that is integral to a cited paper, such as the image used in HD 80606 b;
* user-generated images that clearly illustrate published properties, such as the size comparisons currently used in GJ 1214 b or Gliese 436 b.

My edits followed these guidelines but were revered by User:MarioProtIV.

Habitable zone comparisons belong in the orbit and/or habitability sections, not in the infobox.

A useful radius comparison to Earth in the relevant section of the article was also removed.

I'm opening discussion as to why ...

--EvenGreenerFish (talk) 09:26, 21 April 2017 (UTC)

I would like if the discussion was held here, rather then on all of the other pages. Plus there is already a size comparison in the graphic in the infobox. --MarioProtIV (^talk/_contribs) 11:19, 21 April 2017 (UTC)

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The Distance from Earth in the summary

Kepler-186f (also known by its Kepler Object of Interest designation KOI-571.05) is an exoplanet orbiting the red dwarf Kepler-186,[5][6][7] about 500 light-years (171 parsecs, or nearly 5.298×1015 km) from the Earth.[1]

So the exact distance is 558 Light years from Earth. If we are to round it to a hundred the correct round up should be to 600 ly's not 500. But it looks like it is best to write about 550 for a closer description. So I'm changing it to 550 ly's. --Erman (talk) 11:56, 5 January 2018 (UTC)

Another note regarding the distance - in one place it is said to be 490 light years (involving how long ago the signals received from the star system were transmitted), whereas at another (in the beginning of the article) it is said to be about 550. This is a huge difference.. Which one is accurate? — Preceding unsigned comment added by 109.65.251.175 (talk) 22:01, 31 March 2019 (UTC)