Talk:GJ 1214 b

Please Put Stats in Laymen's Terms

Data about the planet is listed in the box in mathematical terms not readily intelligible to the general reader. It would be helpful if this display could at least include accompanying listings formulated in commonly understood units of measurement. For example, how long does it take for this planet to orbit its sun? thirty eight hours?

Features

large quantities of liquid water could persist, some of which could be in the form of ice VII How can liquid water be in the form of Ice VII, which is a cubic crystalline form of ice? Why mention Ice VII at all? Qemist (talk) 00:10, 27 December 2009 (UTC)

I removed the claim that Ice VII is a form of liquid water. Qemist (talk) 11:20, 28 January 2010 (UTC)

Artist's conception?

Would this article benefit from an artist's impression of the planet? If so, drop me a line with technical constraints. de Bivort 05:24, 17 December 2009 (UTC)

There's a general discussion of the appropriate use of artist's impressions of exoplanets on the planetbox template's talk page. — Aldaron • T/C 15:29, 20 December 2009 (UTC)

Exactly, there's no actual evidence the thing exists. It is just theoretical interpretation of data and statistics.72.161.86.201 (talk) 08:44, 22 February 2012 (UTC)

An interpretation of data and statistics is nearly the exact definition of "actual evidence." But, more importantly, do you have a suggestion for the article? de Bivort 10:08, 22 February 2012 (UTC)

Semimajor axis

The quoted semimajor axis (0.06816 ua) is inconsistent with the quoted period (1.58 days) given the star mass 0.157 given by exoplanet.eu. The same source gives a semimajor axis of 0.014, which is consistent with the period. If the semimajor axis is 0.014 then the temperature estimates given in the article become implausible because the implied irradiance is about 17 times terrestrial. Qemist (talk) 07:02, 17 December 2009 (UTC)

Probably better data are available from the paper. Check the arXiv copy, it is in the references in the article. --Cyclopia^talk 11:26, 17 December 2009 (UTC)

Irradiance at .0143 AU is L/(4pi R²) = 22744 W/m²; so T = (22744/(4 sigma))^(1/4) = 560K for a blackbody. (the 4x factor arises from the ratio of illuminated surface to total surface). This is reasonably consistent with the article. -- 99.233.186.4 (talk) 16:35, 21 December 2009 (UTC)

Size comparison box

I would like to insert the size comparison box, but it becomes pretty large. Any suggestion? --Cyclopia^talk 11:26, 17 December 2009 (UTC)

Something needs to be done about this template: it needs to be possible to scale the graphic to a specified size, or, perhaps better, it ought to always produce a fixed sized result. — Aldaron • T/C 04:36, 18 December 2009 (UTC)

Well its not much of a Size Comparison if both are looking roughly the same size. Afro (Not a Talk Page) ^{- Afkatk} 07:57, 20 December 2009 (UTC)

The graphic, as a whole, of course. — Aldaron • T/C 15:14, 20 December 2009 (UTC)

eh?

For the benefit of non-astronomers, if the temperature is more than 120C, how come the water doesn't boil?

Pressure. — Aldaron • T/C 15:33, 19 December 2009 (UTC)

Because of the extra pressure. But you would think at 500c it wouldn't be water. Most likely a very very thick Atmosphere like a super venus. I believe that should be noted as the most likely. /// —Preceding unsigned comment added by Matthurricane (talk • contribs) 06:27, 20 December 2009 (UTC)

Super-Earth and Super-Venus are pretty much the same thing. The problem with calling it a Venus is that Venus has almost no water. -- Kheider (talk) 08:28, 20 December 2009 (UTC)

Surely atmospheric pressure depends on surface gravity ? And although the planet has a mass 6.55 times that of Earth, its lower density/larger radius means that its surface gravity is only 0.9 g. So the high atmospheric pressure explanation doesn't seem to be consistent with the given mass and radius. Maybe there is a better explanation in the original Nature article, but I can't access that. Gandalf61 (talk) 11:39, 20 December 2009 (UTC)

It does not only depends on the surface gravity but also on the mass of the atmosphere per surface area.

The mass is primarily limited by the ability of the gravity to prevent the gases from escaping to space. Since the gravity decreases much slower with height it can hold more atmosphere than the earth. —Preceding unsigned comment added by 82.209.155.237 (talk) 15:27, 20 December 2009 (UTC)

The water is under a lot of stuff. Picture a thick H/He atmosphere where our crust and upper mantle would be, with water where our mantle lower mantle and outer core would be. — Aldaron • T/C 15:18, 20 December 2009 (UTC)

So just how does the planet hold any significant amount of H/He, let alone a thick atmosphere, with a surface gravity of only 0.9 g ? I'm not buying the "gravity decreases much slower with height" point - altitude to top of mesosphere, 50 miles, is less than 2% of Earth's radius - so gravity at that height is still more than 96% surface gravity; decrease of gravity with height is not a significant factor within the atmosphere. Gandalf61 (talk) 18:53, 20 December 2009 (UTC)

The Exosphere reach much further out about, 190,000 kilometers on the earth. Since the atoms has an random speed distribution in this very thin gas some fraction will have reached escape velocity and escape in to interplanetary or interstellar space. After some time (1e9 years) there will bee a balance between influx of gases to the atmosphere (from the surface and from space) and the gases that escapes to space. So the important thing here are the escape velocity. 81.234.184.49 (talk) 23:29, 24 December 2009 (UTC)

Just below the critical pressure of 218 atmospheres, the boiling point of water is 374°C (705°F) if I'm not misreading my physical tables (or else imagine the general principle). Just consider an espresso machine, and the image becomes pleasant! (? ;-) A Super-Earth does just refer to the mass only, less than f.ex. Uranus or Neptune but more than Earth. "Super-Venus" is not a term, such a body would be called a "Super-Earth". ... said: Rursus (^mbork³) 17:39, 20 December 2009 (UTC)

Percentages

Are these percentages plausible? 75% water and 25% rock? That's a really small core of rock surrounded by an enormous amount of water. The Earth has a lot of water on its surface, but that's a very small percentage of what makes up the Earth as a whole. -- Evertype·✆ 12:51, 20 December 2009 (UTC)

Yes, that's the correct (or at least one possible very likely) composition, which would be very different from that of Earth, Venus, or Mercury. — Aldaron • T/C 15:13, 20 December 2009 (UTC)

Actually according to Charbonneau et al. the measured radius is too great for even a pure H₂O planet. The radius of GJ 1214b lies 0.49 ± 0.13 R_E above the water-world curve (caption to their figure 3). Therefore there must be a deep (0.49 R_E is 3120km) atmosphere to explain the transit radius. The paper Three Possible Origins for the Gas Layer on GJ 1214b is of relevance. Qemist (talk) 22:04, 23 December 2009 (UTC)

following are some densities for comparison. the composition has to be something that adds up to ~1.8 g/cm³ overall. this very probably means presence of water, carbon monoxide, or carbon dioxide...

substance       density g/cm³
water           1.0
carbon monoxide .789 (liquid)
carbon dioxide  0.770  (liquid at 56 atm and 20 °C) 
                1.562  (solid at 1 atm and -78.5 °C)
carbon          1.8 - 2.1 
quartz          2.65
fused silica    2.2
metallic Si     2.329 
iron (III) oxide  5.242 
iron            7.874 

-- 99.233.186.4 (talk) 03:56, 21 December 2009 (UTC)

Well, it's obvious there isn't solid or liquid carbon oxides, not at this proximity to the parent star. -RadicalOne---Contact Me 04:01, 21 December 2009 (UTC) That leaves...water and carbon, with a small amount of something else. -RadicalOne---Contact Me 04:01, 21 December 2009 (UTC)

I'm not really getting how that's obvious, since Venus has quite a lot of CO2. But i do see further indications that hydrogen and helium could be depleted: "The defining criterion for an ice giant seems to be the accretion of enough frozen volatiles (water, methane, ammonia) around a heavy-element core to retain a hydrogen-helium atmosphere comprising about 10% of the object’s total mass. Theoretical studies indicate that about 10 earth masses is the minimum mass needed to sustain such an atmosphere (Pollack et al. 1996)."[1] -- 99.233.186.4 (talk) 18:00, 21 December 2009 (UTC)

Those densities aren't relevant because they are measured at 1 bar pressure. At the higher pressures in the interiors of planets materials become denser. For example, ice X has a density of 2.51g/cm³. Qemist (talk) 22:14, 23 December 2009 (UTC)

Also, for comparison, Earth's density is around 5500 kg/m³, so whatever this planet is made of, it has to be a lot less dense than Earth. —Preceding unsigned comment added by 71.104.20.234 (talk) 17:43, 21 December 2009 (UTC)

Water

Is there direct evidence for H₂O on this planet? If not we should probably say that. --Cam (talk) 16:14, 20 December 2009 (UTC)

I really doubt there is liquid water on this planet. The trouble is, that with such a short orbital period, tidal forces have most-probably pushed this into synchronous rotation. This would lead to atmospheric storms like venus, and nil magnetic fields, promoting large losses via dissociation and escape of the hydrogen. -- 99.233.186.4 (talk) 17:37, 20 December 2009 (UTC)

Except that this planet likely has a very thick layer of hydrogen and helium as is; that would protect the water from a large fraction of the radiation. Furthermore, the star is a fairly weak one, so the rate of gas loss would be orders of magnitude less than a planet around a star like Sol. -RadicalOne---Contact Me 17:42, 20 December 2009 (UTC)

actually, solar wind from a small star would be strong at this planet's distance. with synchronous rotation, one face is heated dramatically, compelling us to conclude that substantial convection must occur, probably in both atmosphere and "ocean". atomic molecular hydrogen and helium loss rates depend on what fraction of the gas has the needed escape velocity -- which at the surface is V_e = sqrt(2GM/r)= 17.5km/s, (cp. Earth's is 11.186 km/s). Quoted temperatures of 393–555 K are calculated values that yield rms speeds of 1.57 to 1.86 km/s for helium. Note, though, that for a helium atmosphere to be stable over billions of years, these respective velocities must be > 10x apart. But at the hot side of this it doesnt quite make it, leading to the conclusion that H and He could be depleted. -- 99.233.186.4 (talk) 22:04, 20 December 2009 (UTC)

Why would one face be heated dramatically? A thick atmosphere can redistribute heat so that the temperature difference between the hemispheres is negligible. I don't see why we are "compelled" to accept substantial convection. Convection occurs when there is heating from below. It is not forced when there is heating from above, such as by incident star light. The formation of atomic hydrogen depends on photodissociation, which would occur at far lower rates around a quiescent red dwarf. The et al. discuss atmospheric mass loss, and I think that source should be preferred to your original research. Qemist (talk) 22:24, 23 December 2009 (UTC)

Oh, I always defer to reliable secondary-sourced information. There are only 3 mechanisms for heat transfer: conduction,convection, and radiation; are you claiming that the light side and the dark side can be at the same temperature with no convection? that's bizarre. To argue about photodissociation, we have to compare circumstances quantitatively: colour temperature of Gliese 1214 = 3000 K; Sol = 5778 K. Irradiance at planetary orbit: Gliese 1214 b = 22770 W/m²; Earth = 1360 W/m². Looking at the blackbody, [2], take the curve for 3000K and scale it a factor of 22770/1360=16.7, then compare. By the way, the authors of the Nature article calculate a time of 700M years for depletion of the atmosphere. -- 99.233.186.4 (talk) 16:42, 26 December 2009 (UTC)

The main mechanism by which heat is redistributed on a synchronously rotating planet is by winds. You could call these convection but I don't think they are what the average educated reader would think of as convection. The escape of a primordial (H₂/He) atmosphere is what was calculated in Charbonneau et al. and that is already mentioned in the article. If you want to claim that the planet would have lost all its water by this mechanism then you will have to provide credible sources. Qemist (talk) 23:19, 26 December 2009 (UTC)

Naturally. At an estimated age of 6G years, that's enough time to lose a dense H/He atmosphere 9 times over, replenishing it with whatever else may be there: H₂O, CO₂, N₂, Ne/Ar, etc... the process could be very much like what happens to the atmosphere of Venus, with its thermosphere, and Hadley cells and even loss of oxygen. Interestingly, since ice X has a density of 2.51g/cm³, could this thing be entirely water? I suppose settling that will have to wait for atmospheric spectroscopy measurements to be taken. -- 99.233.186.4 (talk) 01:47, 27 December 2009 (UTC)

New observational evidence of a water-based atmosphere, from Subaru Telescope's two optical cameras: http://www.sciencedaily.com/releases/2013/09/130904093259.htm Challenger l (talk) 17:14, 4 September 2013 (UTC)

The key phrase (adapted from Nature paper) is "...planetary mass and radius are consistent with...". Basically there are models of what combinations of mass and radius correspond to plausible planetary compositions. For example the data-fitting mass and radius values are far from what would be expected for an Earth-like planet (67.5% Si; 32.5% Fe) but close to what would be expected for a water-dominated planet (75% H₂O; 22% Si; 3% Fe). That's the basis for the composition claimed in the article, and I think the phrasing is enough to capture that. If we start listing the things about exoplanets for which there is not direct evidence in each article, we're going to have an unreadable mess. That kind of discussions probably belongs in the general articles on exoplanets. — Aldaron • T/C 17:46, 20 December 2009 (UTC)

Sure, we don't have to list everything there isn't direct evidence for in every exoplanet article. I guess my thinking is that this is a special case — since the popular press is presenting this as a "water world," it might be helpful to include a clause like "while no direct evidence for water has been found …" here. --Cam (talk) 18:24, 20 December 2009 (UTC)

In this case, you're probably right. Let's try that. — Aldaron • T/C 18:36, 20 December 2009 (UTC)

Cool, thanks! --Cam (talk) 18:52, 20 December 2009 (UTC)

right. better to wait for direct evidence of H2O, since from calculated density = (6.55 x 5.9736e24) / ((4 / 3) x pi x ((2.68 x 6.371e6)^3)) = 1 877 kg/m^3, this could as easily be liquid CO2 and rock. -- 99.233.186.4 (talk) 18:44, 20 December 2009 (UTC)

Using what models of planetary formation and composition? — Aldaron • T/C 18:47, 20 December 2009 (UTC)

prior to ignition of the solar furnace, the developing proto disc and exoplanet probably follow ice-giant model such as [3] which says, "carbon planet mass-radius relationships overlap with those of silicate and water planets due to similar zero-pressure densities and equations of state" -- 99.233.186.4 (talk) —Preceding undated comment added 19:06, 20 December 2009 (UTC).

All carbon planets, yes. But there are 3 kinds (modeled in the paper), and only CO (not CO₂, BTW) planets fall near the range of mass and radius fitted for Gliese 1214 b (the others are considerably smaller), and these only form in certain stellar environments not present in this case. — Aldaron • T/C 19:43, 20 December 2009 (UTC)

Surface temperature

These temperature estimates appear to ignore the greenhouse effect a massive atmosphere would surely have. These calculated values correspond to some kind of temperature (probably effective temperature I would guess) but are likely not to correspond to surface temperatures at all. 86.169.213.145 (talk) 18:29, 22 December 2009 (UTC)

Doesn't seem to meet WP:DUBIOUS though: this is exactly what the references say. — Aldaron • T/C 19:02, 22 December 2009 (UTC)

How about actually reading the references? The first one is to the discovery paper, I pulled it off arXiv and it refers to the planet's equilibrium temperature not the surface temperature. The second one gives the planet's temperature without any qualification as to whether the temperature is a surface temperature, equilibrium temperature or whatever. Dubious tags reinstated. 86.169.213.145 (talk) 19:21, 22 December 2009 (UTC)

Wow, that looks like two editors with poor reading comprehension skills. No wonder Wikipedia is full of crap. If you do a search of the discovery paper, as pulled off the arXiv, you will see it does not contain the term "surface temperature" at all. It does on the other hand refer to the equilibrium temperature. Even if you can't be bothered to read your sources all the way through, CTRL+F goes a long way. 86.169.213.145 (talk) 19:31, 22 December 2009 (UTC)

Your point about the temperature is well made, but I think you should take a more collegial tone when addressing your fellow editors. The concept surface temperature is probably not applicable, but, if it is, it will almost certainly be greater than the gray body equilibrium temperature. Qemist (talk) 21:38, 23 December 2009 (UTC)

I appreciate your concerns, so I removed "surface" and used "could be" instead of "is". That said, the statement is sourced and as such there is nothing technically dubious about it: it is a fact that such a conjecture has been published in the discovery paper. Being a conjecture, however, I agree the wording was too strong. I hope this settles the issue. By the way, please stop personal attacks to other editors and be civil, please. Thanks. --Cyclopia^talk 19:36, 22 December 2009 (UTC)

Where does the article say something that's not in the cited references? — Aldaron • T/C 19:35, 22 December 2009 (UTC)

It doesn't say it anymore. This discussion is due to something I added. I was trying to make the text more readable and ended up with Its surface temperature is between approximately 393–555 K (120–282°C or 248–540°F. I used the phrase surface temperature to mean the temperature at the periphery of the planet, rather than the interior (for which there is of course no information at all). This follows the astronomical sense where the phrase is used to mean the effective temperature at which an object interacts with and emits interstaller radiation. Indeed the Harvard reference uses the term "surface temperature" in this sense for the star itself; to mean the apparent external temperature, though a star, being hydrogen, doesn't actually have a surface at all. I'm equally happy with the terms "equilibrium" temperature or "effective" temperature if it makes everyone happier. Thank you to whoever changed it.

As for the other comments made, I don't know what the Nature reference says, because I don't have subscription access to it; and I have no idea what CTRL+F does either. —Preceding unsigned comment added by Hallucegenia (talk • contribs) 21:30, 22 December 2009 (UTC)

CTRL+F is for "text searches". When you are inside the arXiv:0912.3229 PDF file you can search (ctrl-f) for the word temperature. -- Kheider (talk) 22:43, 22 December 2009 (UTC)

No problem. Things seem to have been settled. — Aldaron • T/C 21:34, 22 December 2009 (UTC)

It's not a conjecture, it is a precisely defined physical quantity that is related to energy absorbed from the star's radiation, which is derived from a simple calculation that anyone with a halfway decent physics education would be able to do. However it is not what is usually meant by temperature, so calling it just plain temperature is misleading. Quoting these values as the temperature of the planet is the same as quoting the temperature of Venus as -41 degrees C (see black body temperature at http://nssdc.gsfc.nasa.gov/planetary/factsheet/venusfact.html). This is exactly the same mistake that was made when Gliese 581 c was trumpeted as a habitable planet based on its calculated equilibrium temperature... the fact the media accepted that story at the time indicates just how bad the state of science education is. 86.169.213.145 (talk) 22:47, 22 December 2009 (UTC)

Were you editing as User:GabrielVelasquez in the past? But anyway, we're not talking of science education here. We're reporting the Nature paper. If you have problems with the paper, please contact the authors, not us. --Cyclopia^talk 22:56, 22 December 2009 (UTC)

The Nature paper uses the term "equilibrium temperature". No problems with that at all (and even if there had been problems there anyone who knew anything about physics would surely be able to point out it is wrong... oh wait, Wikipedia has that no original research policy with which it is possible to stamp out such applications of common sense). It then gets reported here as "temperature", which most people will interpret as the reading you get when you land your spaceship on the planet and stick the thermometer outside the door. Which it isn't. And that mistranslation of the concept isn't the fault of Nature, is it now? 86.169.213.145 (talk) 23:09, 22 December 2009 (UTC)

You have a point. Will edit to reflect that. --Cyclopia^talk 23:19, 22 December 2009 (UTC)

Actually, the Nature news article says "equilibrium surface temperature"—wrong and confusing, perhaps, but still a perfectly understandable reason for the initial wording, which thus (and actually on first principles) hardly warrants the viscousness of your attacks. — Aldaron • T/C 23:25, 26 December 2009 (UTC)

Again key word there is "equilibrium", which implies this is not the temperature you get when you stick the indestructible thermometer out of the door of your indestructible spaceship. All you are doing is showing you would blindly copy the source without any real understanding of what is going on. I don't know whether that's because you either don't understand the concepts you are dealing with as regards temperature, or whether Wikipedia is being hamstrung by idiots wannabe lawyers using the no original research policy to remove all trace of basic physics and common sense on the part of editors from the articles. 86.148.145.35 (talk) 18:28, 27 December 2009 (UTC)

Sorry, I'm not even the guy who made the "offending" edit. I'm just pointing out that the belligerence was uncalled for—as you nicely demonstrate above. — Aldaron • T/C 19:26, 27 December 2009 (UTC)

See template discussion. — Aldaron • T/C 18:48, 23 December 2009 (UTC)

The thing i love about Nature caliber articles is that the authors define their goal posts. They make it clear in their text that the estimated radius is the radius at a pressure of 1 millibars, with a scale height of 233 km. If we take the 1-millibar point as a virtual surface, then everything else makes a lot of sense. As for greenhouse effect, it is highly dependent on atmospheric composition. We could compare the absorption spectra for various atmospheric compositions via charts very much like [4], but these are shots in the dark until someone actually tries to measure the planet's atmospheric composition. -- 99.233.186.4 (talk) 06:02, 28 December 2009 (UTC)

The claim that the transit radius corresponds to the "1 millibar" level doesn't seem well supported by the literature. The Nature article refers to A THEORY FOR THE RADIUS OF THE TRANSITING GIANT PLANET HD 209458b by Burrows et al. It merely states

Hence, since the pressure level to which the transit beam is probing near the planet's terminator is close to 1 mbar (Fortney et al. 2003),

Reference to the bibliography expands this as Fortney, J. J., Sudarsky, D., Hubeny, I., Cooper, C. S., Hubbard, W. B. Burrows, A., & Lunine, J. I. 2003, ApJ, 589, 615. Using my university library and Google reveals this to be On the Indirect Detection of Sodium in the Atmosphere of the Planetary Companion to HD 209458 (doi: 10.1086/374387). This paper makes no general statements about what pressure level corresponds to a transit radius and the statements it does make about the likely position of cloud decks (eg clouds arise naturally in the planet's atmosphere near ~1-5 mbar) are quite specific to the hot Jupiter HD 209458b. Qemist (talk) 06:13, 29 December 2009 (UTC)

Well, I suppose clarity lies in the eyes of the beholder. It should be reasonably straightforward even for us non-experts to apply the principles of scale height and transmittance to an arbitrary chord of a planet's atmosphere to predict the amount of attenuation of the parent star's light. After that, if you disagree that 1 millibar is about right, then it will be time to send a letter to the editors of Nature. -- 99.233.186.4 (talk) 01:28, 10 January 2010 (UTC)

That would be a simplistic calculation if it were possible, and it is not. The composition of the atmosphere is unknown. Qemist (talk) 10:07, 10 January 2010 (UTC)

Regardless of whether it's simplistic, you can calculate, for a chosen value of pressure, the amount of the planet's atmosphere that a ray of light travels through, before it reaches us. So for 233km scale height, r=2.678_e, p=1mbar max, I get 2806km. Different compositions will attenuate differently at different wavelengths; but let's assume visible light and H+He in the atmosphere as claimed, then just apply the right dB/km. -- 99.233.186.4 (talk) 14:54, 10 January 2010 (UTC)

I really don't know why you bother to post stuff like this. It's clearly OR. This isn't a general astronomy forum. —Preceding unsigned comment added by Qemist (talk • contribs) 04:15, 11 January 2010 (UTC)

New file

Should this image be included in the article? It is licensed under Creative Commons ShareAlike 3.0. --The High Fin Sperm Whale (Talk • Contribs) 22:01, 22 December 2009 (UTC)

See the discussion of the appropriate use of artist's impressions in exoplanet articles. — Aldaron • T/C 22:06, 22 December 2009 (UTC)

Well then somebody should change the main page picture. If the picture has no qualification, out with it, otherwise, put it back in the article. Don't have a picture on the main page and then argue with people when they try to insert it into the article. I notice the picture is made by a member of the community, so lets get it off the Main Page. - ʄɭoʏɗiaɲ ^τ _¢ 03:26, 23 December 2009 (UTC)

Your point? — Aldaron • T/C 03:34, 23 December 2009 (UTC)

You need the tl;dr? Getting the image off the main page since it is original research. - ʄɭoʏɗiaɲ ^τ _¢ 03:44, 23 December 2009 (UTC)

I agree, let's get it off the main page. Only admins can edit ITN though. — Aldaron • T/C 03:54, 23 December 2009 (UTC)

For a dumby like me

There are several statements in this article that Don't seem to make sense to me. First off; if the planet is really so close to it's star (0.014 AU = only 1,300,000 miles) it seems like it should be boiling hot (probably at least 2000 K). Someone calculated it's blackbody temperature as 550 K by taking 22,744 K (where they got this number I don't know; By the way what does the "L" in the equation stand for?) raised to the 1/4 th power; the last time I checked 22,744^1/4 is approximately 12.27 (liquid hydrogen range). Would someone be kind enough to explain this better to my Mechanical Engineering degreed self? — 66.213.36.2 (talk) 20:47, 23 December 2009 (UTC)

L here is luminosity of the star, in Watts; the 22744 is not Kelvin, it is Watts/m², and equals the luminosity divided by the area of space at R=.0143 AU. At equilibrium temperature, heat loss by radiation (which increases with T⁴) equals heat gain by illumination. Illuminated surface of the planet is pi r²; whereas its total surface is 4pi r²; remember to include the Stefan-Boltzmann constant. -- 99.233.186.4 (talk) 15:47, 26 December 2009 (UTC)

What is meant by "Equilibrium Temperature" and why would Tidal Locking cause a weak Magnetic field (so what if the liquid portion of the planet did not rotate; if the solid part was hot enough couldn't there still be convection induced magnetism? — JeepAssembler (talk) 20:53, 23 December 2009 (UTC)

First of all, this is a page to discuss about the article, not the article subject. However, I try to give my 0.02 £ :

1)No, it is not boiling hot because the parent star is very cold -actually, the star itself is not much hotter than 2500 K

2)I don't understand the question, nor I know the equation you are talking about; please see the original paper however to see

3)I guess it is the temperature as if the planet is considered a simple ball with a certain albedo, ignoring atmospheric greenhouse effects etc.

4)Nice idea, but you better ask some real planetologist or geologist (I am not). --Cyclopia^talk 22:52, 23 December 2009 (UTC)

According to Gliese 1214 the star's temperature is about 3000K. The two editors' questions could be best answered by their reading the relevant Wikipedia articles. Although their questions weren't addressed to improving the article, they may be symptomatic of its being too technical, or too short. Qemist (talk) 01:38, 24 December 2009 (UTC)

Assumed to be similar to neptune 2010/12/02 research

the research actually seems to say that the planet is NOT similar to neptune, here is a link to a bbc article about the research: http://www.bbc.co.uk/news/science-environment-11886942

approximately 8 paragraphs from the bottom "For Dr Bean, that means that GJ 1214b must not be an icy "mini-Neptune" with a hydrogen or helium atmosphere." —Preceding unsigned comment added by 81.141.189.6 (talk) 20:00, 9 December 2010 (UTC)

Waterworld confirmed

Distant 'waterworld' is confirmed, BBC News, 21 February 2012. Connolly15 (talk) 17:08, 21 February 2012 (UTC)

Having actually 0 knowledge on any of this will leave it up to the more experienced. I clicked through to the article referred to from Astrophysical Journal and it does not even mention the word water in the abstract (then again I didn't understand much of what was said at all!) Connolly15 (talk) 17:13, 21 February 2012 (UTC)

I read the nature abstract [5] and it says a water based world is consistent with the observations but so are alternative planetary models, like a cloudy atmosphere.--Nowa (talk) 22:42, 21 February 2012 (UTC)

That Nature article is a previous paper. Here is a freely-accessibile "beta version" of the new study on arxiv that suggests the light (primarily Hydrogen) hazy atmosphere scenario is inconsistent with evidence, The Flat Transmission Spectrum of the Super-Earth GJ1214b from Wide Field Camera 3 on the Hubble Space Telescope (click "PDF" to the right to get a pdf copy of the full paper). Note particularly the conclusions section. That being said I don't think the story is over as I believe there are more studies being written up by other teams which show different results. ChiZeroOne (talk) 12:59, 22 February 2012 (UTC)

Thanks. Very interesting.--Nowa (talk) 17:24, 22 February 2012 (UTC)

Kevin

Just read an article in my local paper regarding the whole waterworld idea. Apparently this planet is nicknamed Kevin, after Kevin Costner in Waterworld. I believe it was the scientists who were studying it using this nickname, but I'll have to double check (left the paper in my car). Should this be added to the article (pending the source obviously)? - ʄɭoʏɗiaɲ ^τ _¢ 17:11, 23 February 2012 (UTC)

I would say no, as it gives their nickname for the object undue weight. In a small number of cases such nicknames may be appropriate to include such as Kepler-16b and "Tatooine" as such a link was made in most of the discussion of that object after its discovery and the use of "Tatooine" to refer to this planet can be clearly cited from a whole range of sources. On Wikipedia we respond to general usage, we don't report on things we think should be. ChiZeroOne (talk) 11:59, 24 February 2012 (UTC)

Or we report things that are quoted. It's not undue weight to indicate a fact, that the scientists used that nickname and that is the reasoning behind it, not sure where you would get that idea... - ʄɭoʏɗiaɲ ^τ _¢ 17:04, 1 March 2012 (UTC)

Requested move

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the move request was: moved. Pretty clear consensus to move. Regarding the spacing of the b, I went with the spaced b because (a) that was the old title and (b) all other Gliese and GJ articles seem to space the b. Feel free to start a new RM about the spacing if you want. Talk pages histmerged. Jenks24 (talk) 10:28, 27 June 2012 (UTC)

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Gliese 1214 b → GJ 1214 b – Per discussion at Wikipedia talk:WikiProject Astronomical objects#Gliese vs. GJ this should be at GJ 1214 b, not Gliese 1214 b. Stars in the Catalogue of Nearby Stars with numbers 1000-1294 are from the 1979 extension published by Gliese and Jahreiß - these should be designated with "GJ" not "Gliese". Furthermore the star's entry in the CNS lists the designation as "GJ 1214" [6], as opposed to stars with numbers <1000 e.g. Gliese 876 which it is listed as "Gl 876" [7].relisting see below Andrewa (talk) 06:40, 19 June 2012 (UTC)46.126.76.193 (talk) 22:21, 11 June 2012 (UTC)

Survey

Feel free to state your position on the renaming proposal by beginning a new line in this section with *'''Support''' or *'''Oppose''', then sign your comment with ~~~~. Since polling is not a substitute for discussion, please explain your reasons, taking into account Wikipedia's policy on article titles.

• Support move to GJ 1214b, as (1) this seems to be the most common term used in the refs and (2) it avoids the problem of the duplicated talk page at Talk:GJ 1214 b. Hallucegenia (talk) 13:05, 25 June 2012 (UTC)

Discussion

Any additional comments:

That discussion is archived at at Wikipedia talk:WikiProject Astronomical objects/Archive 22#Gliese vs. GJ. Wikipedia:Official names is probably also relevant.

There are some quite complex issues and I don't think the archived discussion makes the conclusion and its rationale plain. As many other articles are involved and no other editors have commented here, worth a relisting IMO. Andrewa (talk) 06:51, 19 June 2012 (UTC)

Further evidence from the references in this article:

• Reference 1 available freely online at [8] uses "GJ 1214b", not "Gliese 1214 b".
• Reference 2 available freely online at [9] uses "GJ 1214b", not "Gliese 1214 b".
• Reference 3 available freely online at [10] uses "GJ 1214b", not "Gliese 1214 b".
• Reference 4 available freely online at [11] does not mention this object.
• Reference 5 available freely online at [12] uses "GJ1214b", not "Gliese 1214 b".
• Reference 6 available freely online at [13] is incorrectly cited in this article, the correct title is "A ground-based transmission spectrum of the super-Earth exoplanet GJ 1214b" (per the Nature link [14]) not "A ground-based transmission spectrum of the super-Earth exoplanet Gliese 1214 b". It uses "GJ 1214b" not "Gliese 1214 b".

So looking at the references linked here only, the GJ form appears to be used exclusively, with some variations in spacing. In fact, by far the most common form is "GJ 1214b". Wikipedia seems to have a convention of separating the letter designation with a space, this form is also used at SIMBAD: [15]. 46.126.76.193 (talk) 18:38, 20 June 2012 (UTC)

• Comment: I believe the wiki-consensus is to name Gliese stars with 3 numbers in the form Gliese XXX while the consensus with 4 numbers is GJ XXXX. -- Kheider (talk) 18:55, 20 June 2012 (UTC)

• Question. Judging from Talk:GJ 1214 b, this page was moved from GJ 1214 b in February 2012, but not using the standard procedure. Was this discussed at the time? (and if so, where is that discussion?) Hallucegenia (talk) 17:33, 22 June 2012 (UTC)
  • It seems to have been done by User:Metebelis who apparently went on a one-person campaign to change all articles with "GJ" in their titles to "Gliese" at one point. Doing this is perfectly fine for stars with CNS numbers below 1000, but for stars above 1000 (e.g. GJ 1214) this is incorrect. Certainly I find it very weird to see this entry listed as "Gliese 1214 b" because none of the sources refer to it as such. 46.126.76.193 (talk) 21:18, 24 June 2012 (UTC)

Thank you for the info. That's good enough for me. I suggest that if nobody objects within seven days, that we go ahead and move this to GJ 1214b. Hallucegenia (talk) 13:01, 25 June 2012 (UTC)

and by the way, I do mean "GJ 1214b" and not "GJ 1214 b" becasue that is what the referenced sources use. Hallucegenia (talk) 07:17, 26 June 2012 (UTC)

I personally have no preference between "GJ 1214b" and "GJ 1214 b", they are both equally valid forms of the designation, I suggested the spaced form because that was what it was before the incorrect move to Gliese. Not sure what can be done about the state of the talk pages though... 46.126.76.193 (talk) 16:49, 26 June 2012 (UTC)

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Request move (Again)

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

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I'm re-request a move from GJ 1214 b to Gliese 1214 b for 2 reasons.

• 1st According to WP:NC article names should be consistent with similar articles 'GJ' is short for 'Gliese' and most articles on Wikipedia use the word 'Gliese' over 'GJ' and you can clearly see this on the Gliese Exoplanet Catagory or on the Gliese Catalogue of Nearby Stars

• 2nd According to MoS "An acronym should be written out in full the first time it is used on a page"

The changed name would fit better with other Exoplanets and stellar objects that are in the Gliese Catalog. Agian this is all about consistency, being consistent with everything else in the same catalog should really be something disputable. Davidbuddy9 (talk) 20:17, 17 August 2015 (UTC)

I would post about this in WT:WikiProject Astronomy if you really want to change it. It seems from prior discussions in the above sections and here that (for reasons I don't understand),Gliese works for numbers <1000, but it is important to use GJ for numbers >1000. A2soup (talk) 20:52, 17 August 2015 (UTC)

I've been asked to participate in this discussion as a way to congenially help reach a consensus between editors who may disagree with edits. In this case it appears as if it is a move that is being discussed-so I'll treat it the same way.

My very first and uninformed impression is that if I were a reader of the article, I would be searching under "Gliese" rather than its acronym. Since my job is to give priority to resolving editor disputes and I will probably comment mostly on resolution than content. I only see one small civil discussion appearing on the page so far. Have you really reached the point where you want my input as an uninvolved editor? Have we already reached an impasse? I am going to take a look at the links listed above to orient myself to the topic and prior discussions and then leave a longer comment. Best Regards,

  Bfpage |leave a message  01:51, 26 August 2015 (UTC)

It appears that a more robust discussion is taking place on WT:WikiProject Astronomy and so that is where I will leave most of my comments. Best Regards,

  Bfpage |leave a message  02:03, 26 August 2015 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Distance from the Sun

From this article: Its parent star is 42 light-years from the Sun

On the page for Gliese 1214: It is located at a distance of approximately 47 light years from Earth.

There seems to be some contradiction here, which of these are accurate? — Preceding unsigned comment added by FreezerGalaxy (talk • contribs) 10:44, 13 May 2017 (UTC)

References

Requested move 6 May 2023

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion.

The result of the move request was: Moved (non-admin closure) >>> Extorc.talk 10:22, 28 May 2023 (UTC)

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• Gliese 1214 b → GJ 1214 b
• Gliese 1002 → GJ 1002
• Gliese 1002 b → GJ 1002 b
• Gliese 1061 → GJ 1061
• Gliese 1062 → GJ 1062
• Gliese 1132 → GJ 1132
• Gliese 1132 b → GJ 1132 b
• Gliese 1214 → GJ 1214
• Gliese 3021 b → GJ 3021 b
• Gliese 3293 → GJ 3293
• Gliese 3323 → GJ 3323
• Gliese 3512 → GJ 3512
• Gliese 3634 → GJ 3634
• Gliese 3634 b → GJ 3634 b
• Gliese 3685 → GJ 3685

– Per WP:STARNAMES, this discussion, and 2012 RM above. I've already moved GJ 3470 and GJ 3470 b. SevenSpheres (talk) 17:48, 6 May 2023 (UTC) — Relisting. >>> Extorc.talk 10:07, 14 May 2023 (UTC) — Relisting. Sceptre (talk) 11:08, 21 May 2023 (UTC)

Note: WikiProject Astronomy has been notified of this discussion. – MaterialWorks 14:49, 22 May 2023 (UTC)

Support, per my comments here and here. Our article on Gliese catalogue also makes it clear that entries over 1000 use the GJ prefix, only those <915 use Gliese. Modest Genius ^talk 11:01, 26 May 2023 (UTC)

Support per the naming convention given in the nomination and for consistency. These stars are probably far too dim to be given Greek titles. Iggy (Swan) (Contribs) 16:43, 26 May 2023 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.