Talk:Super-Earth/Archive 1

Archive 1

Rivera is from Gliese 876 d

"There have been several discoveries of Super-Earths since the first discovery in 2005 by a team lead by Eugenio Rivera of Gliese 876 d."

This makes it sound like Rivera is from Gliese 876 d....--Blingice 21:37, 27 April 2007 (UTC)

Copyright Violation

I'm not sure how to report this, but it seems a section of this article ("Super earth found on June 2008") is lifted from a Reuters news report. [1] 66.17.118.195 (talk) 16:35, 16 June 2008 (UTC)

Issue has been addressed. Best, Themanwithoutapast (talk) 18:14, 16 June 2008 (UTC)

misnomer

If the misnomer use is more widespread that the "correct" use, then the *new* usage should be documented in this page or a separate page, as there is no actual real definition, only proposed definitions with varying degrees of acceptance. 70.55.85.40 (talk) 12:35, 12 August 2008 (UTC)

defining characteristics?

The defining characteristic seems to be plate tectonics... in which case, this article seems to be an artificial division between the Earth and other planets that are tectonically active. 70.55.85.40 (talk) 13:02, 12 August 2008 (UTC)

Bot report : Found duplicate references !

In the last revision I edited, I found duplicate named references, i.e. references sharing the same name, but not having the same content. Please check them, as I am not able to fix them automatically :)

• "Valencia" :
  • Valencia et al., Radius and structure models of the first super-Earth planet, September 2006, published in The Astrophysical Journal, February 2007
  • {{cite journal|first=Diana|last=Valencia|coauthors=Dimitar D. Sasselov, Richard J. O'Connell|year=2007|title=Radius and structure models of the first super-earth planet|journal=The Astrophysical Journal|volume=656|pages=545–551|doi=10.1086/509800}}
  • Valencia et al., Radius and structure models of the first super-Earth planet, September 2006, published in ''The Astrophysical Journal'', February 2007

DumZiBoT (talk) 21:44, 12 August 2008 (UTC)

Upper size

Allowing for composition, proximity to star, effects of other planets in the system and "other relevant factors" is there a likely maximum size (mass or volume) for rocky/terrestial planets? From what I understand Earth's size meant that the primordial gaseous hydrogen etc in the atmosphere escaped the planet's gravity: is there a point/size band above which the planet will become "a gas giant with a rocky core"? Jackiespeel (talk) 15:50, 26 September 2008 (UTC)

Star of 10 Earth Masses?

I quote "A super-Earth is a planetary object orbiting a star, with a mass of between 2 to 5 and 10 Earth masses..." which is badly written, it can be seen as reading that the star is 10 Earth masses. GabrielVelasquez (talk) 00:33, 11 January 2008 (UTC)

Err... that is why we use punctuation, such as commas, to give a subtle hint at the meaning of a sentence...Leave that comma out, and the mass is now that of the star, whereas if we leave it in, the mass is planetary. Admittedly this might be more difficult for non native English speakers, but is correct.85.158.137.195 (talk) 15:23, 8 November 2009 (UTC)Lance Tyrell

Question

Just wondering but is the article implying that these planets could be lived on, or are they just similar to Earth? Evilgidgit (talk) 21:07, 20 December 2009 (UTC)

They are merely similar to Earth in size. "Lived on" is a whole different issue. -- Kheider (talk) 21:51, 20 December 2009 (UTC)

Ah, thanks for the info. Evilgidgit (talk) 13:04, 22 December 2009 (UTC)

Formation location

The lead contains this text, referring to Fortney et al. (2007):

"Also, they are usually relatively close to their parent star(s), because colder, outer planets of that size would lose less gas during formation of a particular solar system and form into full gas giants.[6]"

While I haven't looked carefully through the entire 27 pages, this assertion doesn't seem to be supported by the cited paper. Fortney isn't dealing with planetary formation here per se, and as far as I can see doesn't say anything about where a "super-Earth" would be likely to form.

Perhaps Valencia et al. (2007) was the original source? Still the discussion here doesn't appear to be entirely germane to the location of super-Earth formation either; they simply cite Ida and Lin (2004) in deriving an upper limit of 10 M_e where a planet begins to have a significant amount of H/He. Having looked through this paper (not thoroughly -- it's 55 pages!) I can't find any justification for this claim either. Furthermore, from what I know about planet formation (which is not that much, unfortunately), planets don't lose significant amounts of gas during formation. Gas giants accrete massive amounts of H and He once the cores reach a certain point (~10 M_e, according to Ida and Lin, apparently). Having grabbed this gas, they don't really lose a significant amount over the course of their lifetimes. (Even on a hot Jupiter like HD 209458 b, total gas blowoff is a tiny fraction of the total mass.) Terrestrial planets by definition don't have a lot of gas to lose, even if they end up with no atmosphere at all. So to refer to "gas loss" during formation doesn't seem to me to be correct.

I could be mistaken here -- as I said, I don't know that much about planet formation, and would be happy to have someone show me where I'm mistaken! In the meantime, however, this sentence doesn't seem to be well-supported by the literature, and so I'm going to take it out unless it can be better referenced. J. Langton (talk) 16:23, 19 August 2008 (UTC)

Again, qualifying things from what you know. This is getting tiring. You are ignoring the reality of the term Chthonian planet; It seems to me you tend to do a lot of convenient ignoring of the fact that get in your way. You deleted the comments when you could have, owing to the Chthonian possibility, have just deleted the word "formation". My own issue, I'll tell you straight, I think the misnomer "Super-Earth" is misleading, and does not acknowledge the fact that a so-called super-earth in a relatively closer orbit than Venus is to the Sun would far more appropriately called a "Super-Venus." I saw the addition of the above references and added the misnomer comment, which you deleted in the same edits. It is a misnomer (let's not pretend misnomers don't become popular and are used in "Literature," ie you reasoning is false that because it is used in literature it is not a misnomer.) in the context of anything other than purley a discussion of mass. If you intend to remove all other speculation (other than mass) I can't argue because it is ignorant sloppy scientists who have perpetrated the terms popularity and you can show referencing for its use. but again, articles based on popularity contests not accurate science. When I say "Super-Venus" you know what I mean, but it won't ever be used because we are all supposed to believe a new Earth (Wow!)has be found every time the find a terrestrial planet. GabrielVelasquez (talk) 17:38, 10 September 2008 (UTC)

Instead of using the perjorative term "misnomer", it might be better to state that this is a mass classification only and is not intended to imply anything about the surface conditions on such a planet. I've put in a sentence to this effect in the lead. Icalanise (talk) 23:15, 10 September 2008 (UTC)

There is a marginal case for tbe term "Super-Venus" as distinct from "Super-Earth" - given that Venus has a markedly different atmosphere and geological/tectonic activity (and "geology-as-a-term" will probably be used colloquially for all planets). Mars, however, lies on the continuum which includes Earth. Jackiespeel (talk) 15:50, 26 September 2008 (UTC)

Then again, the term "Super-Venus" does not appear to be in use. I think this just comes down to how the term is intended, it is a mass classification, used to describe a group of planets which have no analogue in the solar system. It is therefore not a misnomer unless you bloody-mindedly insist that the term "Earth" must also imply Earthlike conditions, which from the way the term is used in the literature is clearly not the case: the word refers to the fact that the mass is greater than the mass of Earth (Earth being used as the reference point because it is the most massive non-giant planet in our system), and that's it. Do we object to terming Venus a terrestrial planet, because terrestrial refers to Earth, and the conditions on Venus are extremely different to those on Earth? Icalanise (talk) 17:22, 26 September 2008 (UTC)

That doesn't make any sense at all; who would call Venus "Earth-Like." All the solid planets are terrestrial, including Mercury and Mars. Super-Terrestrial is the default best term, but Super-Earth creates more popularization and press interest, that's obvious. 205.200.236.34 (talk) 04:25, 5 October 2008 (UTC)

How does it not make any sense at all? After all, the fact that "super-Earth" is just a mass classification defined relative to Earth (hence not a misnomer) is abundantly clear from the literature. As for who would call Venus "Earth-like", if you consider the bulk of the planet rather than just the surface conditions, Venus is fairly Earth-like (perhaps more so than Mars is - the uncompressed densities of Venus and Earth are very similar, while Mars has a significantly lower uncompressed density). Note that a lot of the studies of super-Earths deal with their internal structures (e.g. radius predictions which largely depend on the bulk of the planet). Since it is a mass classification, by analogy Earth is a "super-Venus" (just so happens that much of the carbon dioxide atmosphere is locked up in the crust), and "super-terrestrial" would seem to imply something with ice-giant mass. Icalanise (talk) 10:34, 5 October 2008 (UTC)

If the Earth were to drift into the orbit of Venus it would quickly become Venus-like in temperature because at first it would get almost twice the solar radiation that it now gets. Even if the Earth's surface would reflect away much of the radiation, the oceans would absorb much of it. Some of the radiation would evaporate more of the water into the atmosphere as vapor. Water vapor is a greenhouse gas even more powerful than carbon dioxide, and water vapor would prevent cooling. Although the atmosphere would get foggy, temperatures would hardly resemble those of San Francisco. Incoming radiation might diminish (Venus actually gets less sunlight at its surface than the Earth gets at its water or solid surfaces, but the heat on Venus stays there), but not enough to stop the effect of increasing pressure in the atmosphere. Remember: pressure creates temperature. Temperatures would increase rapidly; because the oceans would eventually vaporize completely, the mass of what used to be the oceans of the Earth would create even more pressure than Venus endures -- and the Earth would get even hotter. Such temperatures would release carbon dioxide from carbonate rocks, only intensifying the effect.

Super-Venus, Super-Earth... the planets Venus and Earth are similar enough in mass that techniques that would detect an Earth-mass planet would almost as easily detect a Venus-sized planet. The real distinction would between a planet with Venus-like mass and a planet with Mars-like mass. --Pbrower2a (talk) 01:53, 23 December 2009 (UTC)

Don't forget the origin of the term wasn't so much for scientific use but as shorthand for media. And since most people (certainly most newsweenies) have no idea how big Venus is (or even where it is), but have some notion of Earth's size, it's a convenience... TREKphiler ^{any time you're ready, Uhura} 05:02, 24 December 2009 (UTC)

That's false. The term was coined to mean something quite specific and useful: bigger than Earth but smaller than the gas giants. So while the precise boundaries might not be important, the term wasn't just a "shorthand for media", but was intended to refer to a size range not present in the Solar System. — Aldaron • T/C 05:15, 24 December 2009 (UTC)

K or M dwarf

Please name a Super-Earth that is not orbiting a K or M dwarf. -- Kheider (talk) 18:08, 23 December 2009 (UTC)

Sorry, caught me in mid-move. Back in own section for now. Size range no longer correct and one sentence will do. — Aldaron • T/C 18:26, 23 December 2009 (UTC)

So why do the following not count?

• PSR B1257+12B, orbits a pulsar
• PSR B1257+12C, orbits a pulsar
• 61 Virginis b, orbits a solar-metallicity G5-type star
• HD 1461 b, orbits a metal-rich G0-type star
• COROT-7b, orbits a solar-metallicity G9-type star
• COROT-7c, orbits a solar-metallicity G9-type star

86.169.213.145 (talk) 18:24, 24 December 2009 (UTC)

Kheider objected to my deletion, maybe he knows? — Aldaron • T/C 18:59, 24 December 2009 (UTC)

A SUPER-EARTH ORBITING HD7924 (Jan 2009) stated, "The known super-Earth host stars are all K and M dwarfs". But back then there were only 8 Super-Earths: HD 7924 b (K0V), HD 40307 b, HD 40307 c, HD 40307 d, Gliese 176 b, Gliese 581 c, Gliese 581 d, and Gliese 876 d. But that is a long time ago given all the 2009 discoveries. I just did not want the statement removed without specifying a proper example. PSR B1257+12 does not necessarily count since Pulsars are not main sequence stars, and any object orbiting a pulsar star is in a far different environment than what we would call a traditional planet.

So COROT-7b (discovered in Feb 2009) is the first Super-Earth discovered that orbits a main sequence star that is G class or larger. HD 1461 (G0V) is now the largest main sequence star with a possible Super-Earth around it.-- Kheider (talk) 20:48, 24 December 2009 (UTC)

Ah, Corot-7 use to be classified as a K0V star. The other two main sequence examples are from this month. -- Kheider (talk) 23:47, 24 December 2009 (UTC)

The primary oddness about the B1257+12 system is the source of the circumstellar disc: supernova fallback instead of a collapsing nebula. Other than that, the formation process is likely the same as for other systems of terrestrial-type planets. Yet still they are regarded as totally weird: perhaps because of the old notion that they are worlds that survived the supernova blast (clearly this is not the case due to the mass loss in a supernova being more than sufficient to unbind the system, any survivors would be because of a fortunate supernova kick and would likely be on high-eccentricity orbits). Output of an apparently universal planet-forming process, yet still outcasts from the planetary pantheon. I suppose it helps if they aren't "real planets" if you want to put out a press release claiming a super-Earth is the smallest exoplanet yet discovered... having a planet with only two lunar masses in the lists tends to blast such claims out of the water. 86.169.213.145 (talk) 23:56, 24 December 2009 (UTC)

"Traditional planets", as the public viewed them in the early 90's, are not blasted by a pulsar every second. -- Kheider (talk) 00:11, 25 December 2009 (UTC)

However it is perfectly ok to call the planets orbiting helium-fusing subdwarf B stars (HW Virginis, V391 Pegasi, HD 149382), cataclysmic variables (QS Virginis, DP Leonis), white dwarfs (GD 66) planets. Neutron stars however are right out! 86.169.213.145 (talk) 00:15, 25 December 2009 (UTC)

Planets and exo-planets of the 1990's are not the quite the same as today. Definitions change, but historical usage moves slower. And for the time being, I think the public wants to find an Earth-like planet orbiting a Sun-like (main sequence) star. -- Kheider (talk) 01:19, 25 December 2009 (UTC)

equilibrium temperature

This text seems inconsistent without showing how blackbody temperature of a planet is calculated, since Venus is a lot closer to the sun than Earth:

• "For example, the black body temperature of the Earth is 254.3 K (−19°C or −2°F ). It is the greenhouse gases that keep the Earth warmer. Venus has a black-body temperature of only 231.7 K (−41°C or −43°F ) even though Venus has a true temperature of 737 K (464°C or 867°F )." -- 99.233.186.4 (talk) 19:05, 13 January 2010 (UTC)

Mass, density?

Earth - 12.756km Corot 7B - 18000km *(max)

Unless it is a gaseous planet,

• 2 Masses of earth - 1.2 diameter of earth
• 3 Masses of earth - 1.28 diameter of earth
• 4 Masses of earth - 1.4 diameter of earth
• 5 Masses of earth - 1.5 diameter of earth (depending on internal composition)
• 7 Masses of earth - 1.6 diameter of earth
• 8 Masses of earth - 1.7 diameter of earth
• 10 Masses of earth - 1.8 diameter of earth
• 12 Masses of earth - 2.0 diameter of earth (absolute max)

Gas Giants start to form around 12.5 masses of earth or diameter of 3.0 earths. —Preceding unsigned comment added by 188.220.53.72 (talk) 21:04, 31 March 2010 (UTC)

Double image

The file showing the relative sizes of Neptune, CoRoT-7 b and Earth [2] appears two times in the article. However, I don't feel comfortable enough with the subject to know which of the two copies to remove. Cheers, Numero4 (talk) 04:31, 25 January 2010 (UTC)

One's an image of CoRoT-7 b, the other is GJ 1214 b. — Aldaron • T/C 05:52, 25 January 2010 (UTC)

Good thing I didn't proceed with the edit. Thanks for the quick reply. Cheers, Numero4 (talk) 06:16, 25 January 2010 (UTC)

Do you think it might be worth merging the two radius diagrams to show all four planets (Earth, COROT-7b, GJ 1214b and Neptune) in one image? Would save a lot of back and forth deletion/restoration of images when editors don't look closely enough. Icalanise (talk) 22:26, 28 April 2010 (UTC)

Yes. I've got a list of "combined" images that I'd like to do when I get a chance. Additional suggestions are welcome. — Aldaron • T/C 23:31, 28 April 2010 (UTC)

Krypton?

"the temperature may be high enough for liquid water to be present, even if the planet is closer to the star than Mercury to Sol, it is worth remembering Gliese 876 d orbits a red dwarf." Can somebody explain what was inteded by this? It would seem to me, even orbiting a red dwarf, being closer to it than Mercury to Sol would make the surface temp mightily damned hot (even if it's not in degrees I understand ;p). TREKphiler ^{hit me ♠} 02:32, 7 November 2009 (UTC)

I was wondering the same thing myself. The article states that the surface temp is 650 Kelvins, here is the Conversion from Kelvin to Fahrenheit

[K] × 9/5 − 459.67 = [F]

650K x 9/5 − 459.67 = 710.33F

Liquid water boils at 212 ºF (100 ºC) at standard atmospheric pressure. Obviously all of these calculations are subject to quite a bit of variation, but liquid water will quickly turn into a gas at anything near the temperature stated as far as I am aware. Richie086 (talk) 08:00, 12 July 2010 (UTC)

The reference shows a range of 430-650K: 430K is 314F and may be possible if the pressure is high enough (see: Supercritical fluid). -- Kheider (talk) 15:00, 12 July 2010 (UTC)

Actually, I was thinking about the connection between Mercury, Sol, Gliese, & a red dwarf. Since Gliese 876 doesn't orbit Sol, how does Mercury's orbit have any relevance? Without a clearer explanation of the heat output of a red dwarf v Sol. TREKphiler ^{any time you're ready, Uhura} 22:18, 14 July 2010 (UTC)

Confusing definition

A Super-Earth is the popular misnomer for a large extrasolar terrestrial planet. One criterion used is that it has a least twice the mass of Earth, but less than ten Earth masses. Also, they are usually not lacking in insolation from their parent star(s), as cold planets of that size would lose less gas during formation and form into full Gas giants.

I put the various tags in the above leadin because it confused me. I can understand the term is thought of as a mis-nomer, for one I could not find a consistent definition. I suspect there is no standard definition and it is a media-invented term. Would that be accurate?

Fortney writes ∼5-10 M⊕ planets that some are calling “super-Earths”, and always puts quotes around the term. Fortney uses the terms "terrestrial planets", "terrestrial-type", "terrestrial-sized" and "terrestrial-mass", all except once without quotes.

Second, the "Also, they are usually not lacking..." weakly implies that it is part of the definition, when it seems on further reading that it is a consequence of our model of planetary formation (I think). Maybe it should read "Due to the accepted model of planetary formation such planets would not lack insolation because rocky cores further away would not lose so much gas"? But that also sounds clumsy.

Maybe an explanatory note in the Notes section? "The reason a large (mass > 2 Earth) rocky body cannot exist further from its parent star is there would be sufficient H/He in the early nebula for that body to attract and become a gas giant."? Only if that is correct of course. -84user (talk) 13:23, 17 June 2008 (UTC)

More precisely, that's an issue of being in the right temperature zone. The Earth's gravitation can obviously hold onto methane and ammonia (although both are thermodynamically unstable in the presence of oxygen) and of course water vapor. Such has been true since at least the beginning of life, as is manifest in the chemical composition of living things (almost all biochemicals are methane derivatives). The oceans demonstrate that the Earth can of course hold onto water vapor. Such is not true of either Venus (too hot to hold onto water vapor as anything other than a transitory molecule) and Mars (gravitation too weak to hold onto appreciable water vapor even if it were warm enough to hold liquid water). Those planets have atmospheres rich in carbon dioxide and nitrogen; if they can't hold onto water vapor they can't hold onto two of the other building blocks of life (methane and ammonia).

If the Earth had twice the gravitation it might be able to hold helium, the second-most common element in the Universe, if not hydrogen, and become a gas giant of sorts -- one that can hold helium if not hydrogen. The problem: nobody can yet detect a planetary atmosphere rich in helium yet sparse in hydrogen. Our solar system may be atypical, but even so no planet within it has a combination of gravitation and temperature suitable for holding helium (atomic mass 4) but not hydrogen (2). Uranus and Neptune can hold onto hydrogen gas, but the Earth cannot hold onto helium. The next gas in atomic weight is methane (16), whose scarcity in the Earth's atmosphere results from a chemical equilibrium that disfavors its continued existence. Then come ammonia (17) -- likewise, oxygen makes its presence temporary -- and water vapor (18), which the Earth's gravitation holds and is very stable in all atmospheric conditions.

Helium may be inert, but any gas that can impose pressure upon an atmosphere in the habitable zone also creates a high temperature in accordance with the ideal gas law. Not making an allowance for the effect of radiation of heat, a doubling of the atmospheric pressure doubles the atmospheric temperature and a halving of the atmospheric pressure halves the absolute temperature. --Pbrower2a (talk) 01:29, 23 December 2009 (UTC)

Oh please, the ideal gas law states nothing of the sort. Ideal gas law is pV=nRT - the volume and the amount of the gas also enter into the equation. Since an atmosphere has no hard upper bound, assumption of constant volume is incorrect, if you're adding or removing gas then the assumption of constant amount of gas is incorrect. So adding helium will not necessarily do anything to the temperature, as the volume of the atmosphere and the number of particles will change. Time to do a statistical physics and thermodynamics course maybe? 86.148.145.35 (talk) 11:56, 27 December 2009 (UTC)

But planetary atmospheres are non-homogeneous. Gases heavy enough to drift toward the bottom of the atmosphere tend to concentrate near a planet's hard or liquid surface. Of course there will be radiative effects and convection. Pressure and temperature may not be proportional, but beyond any question they connect strongly and positively. I am well aware that V can change and prevent the proportional connection between pressure and temperature. Of course atmospheric gases warmed more than surrounding ones will expand, become less dense, and rise due to uneven heating of a planet. But when the atmosphere at the planet's surface (assume flatness as a simplification) any increase in pressure results in higher temperature.Pbrower2a (talk) 03:45, 28 July 2010 (UTC)

References

Dubious statement about surface gravity

I think it's a problem that it says "High surface gravity ... is one of the predominant known characteristics of super-Earths." The high surface gravity is not really known, it is implied from theory and highly preliminary observations, correct? When I read known, that says to me that direct observations have been made, like it's known that the surface temperature of Venus is about 480°C. I think the statement should read something like "Little is known about super-Earths, apart from the fact that a large planet with an Earth-like composition would have a surface gravity much higher than Earth's." — Preceding unsigned comment added by Nburns1980 (talk • contribs) 21:04, 1 April 2011 (UTC)

Or here's another accurate rewriting: "Little is known about super-Earths, apart from what can be predicted based on their anticipated high surface gravity." — Preceding unsigned comment added by Nburns1980 (talk • contribs) 21:15, 1 April 2011 (UTC)

two types

This article from Science News, "Super-Earths may come in two flavors" , suggests two distinct populations of Super-Earths with overlapping mass ranges. (perhaps one, superterrestrial, the other subNeptunes/gas dwarfs) 76.65.129.5 (talk) 13:20, 9 September 2011 (UTC)

Gliese 876 d temperature problem

The article states that Gliese 876 d, the first "Super-Earth" to be identified, " may have a surface temperature of 430–650 kelvin and may support liquid water." However, upon converting this temperature into Celsius, I saw that even at its lowest estimate, the surface temperature of the planet would not be able to hold water at 176 degrees Celsius... — Preceding unsigned comment added by Malcolm66 (talk • contribs) 10:58, 30 April 2012 (UTC)

Given the high pressures on Gliese 876 d, I believe liquid water can not be ruled out. There certainly could be a supercritical fluid and/or water vapor. -- Kheider (talk) 11:18, 30 April 2012 (UTC)

20.4 Lightyears Ago, not present

Okay this is only a first grade "Assesment" article but I have to insist that you follow the Encyclopia guidelines to not use spectulation as fact. No "Super-Earth" type planets have been photographed and they are all HPOs (Hypothetical Planetary Objects). The light from these stars is decades, hundred, and in some cases thousands of years old, and so the possibility of a planet still being there is pure speculation!

But this is literally true about EVERYTHING because it always takes light time to travel but by convention we assume that if we see a person who is one light-microsecond away (three football fields) that they actually still exist. Similarly for planets that last for billions of years a couple of hundred years ago isn't a big dea. 74.192.15.216 (talk) 23:36, 18 October 2012 (UTC)

Please refrain from refering to planets, whose signature star-wobble has been detected, as a currently present verifed object. One piece of raw data creating a long list of possible calculated attributes is still catagorically speculation. GabrielVelasquez (talk) 00:15, 1 January 2008 (UTC)

Gabriel, please see planet detection. Yes, the light from Gliese 581 takes 20.4 years to reach the Earth, but that doesn't mean that the star isn't there, or that the planet isn't. Gliese 581 is moving around as though it is being pulled by three planetary mass objects, therefore there are three planets around it (see Ockham's razor). Now, there is a valid criticism of the radial-velocity detection method - technically it only measures minimum values for the mass of the planets. Getting the absolute values will need to wait a while, so that we can measure the perturbations the planets have on each other. But the probability is pretty good that the planets are low enough mass to be solid. Michaelbusch (talk) 02:31, 1 January 2008 (UTC)

Ockham's Razor says "the explanation of any phenomenon should make as few assumptions as possible, eliminating those that make no difference in the observable predictions of the explanatory hypothesis or theory." I can say there are many possible objects that cause the wobble of a star, objects of many possible densities, so you fail to follow this theorem that you quote when you assume a planet size. I doesn't have to be a "Super-Terrestrial" (proper term), when it can be a Gas Dwarf (100% gas for that mass), or a ball of Aluminum. The use of the term "Planet" here is cogent assumption, but nevertheless not a sound assumption. A major error here is the use of the term "Earth," when "Terrestrial" is less of an assumption, as per your quote of Ockham's Razor. You say "Getting the absolute values will need to wait..." which is an admission of the level of speculation involved. And, as it been pointed out to me, this Encyclopedia is about fact not speculation. GabrielVelasquez (talk)

Gabriel, Wikipedia is about verifiability, not just fact. The verified fact is that there is an object with a particular mass in orbit around Gliese 581c. The standard interpretation is that matter over there acts like matter over here and therefore something that low-mass cannot have formed a large gas envelope. That is verified by citing the relevant articles. The uncertainty inherent in that interpretation is already discussed. Adding weasel-words is not required. I referred you to Ockham so that you would accept that the planet was there because its mass is there. I'm afraid I don't see what this discussion will do to improve the article. Michaelbusch (talk) 19:48, 1 January 2008 (UTC)

(a) "Standard interpretation" I'll have to remember that one.

(b) Jupiter formed mostly of gas and I know you would not hesitate to say there is a "Super-Earth" at it's core, and yet compared to the whole mass that Super-Earth would be "Low mass." Also "cannot form" is theory.

(c) "... doesn't mean the star is not there." FALSE: I could like-wise suggest that perhaps you missed the article on "Supernova." You will not know that the star and planet is still there now until 20.4 years from now, When the light that left there now actually gets to here. If we took 20.4 years off your life you would take issue with it: there is 20.4 year difference between "relatively there" and "there now," please take due note of these facts.

(d) I am not going to get into an edit war or start vandalizing because I disagree with this media error circularly supported by popularist scientists. I respect that this is an (an attempt at an) encyclopedia: I just want you to acknowledge that "Super-Earth" is a misnomer. The use of the word Earth does not refer to soil and so it refers to our own planet Earth, and so this is false reason because you cannot prove that these planets are like our planet Earth. The may be closer in size to our planet Earth than Neptune or Uranus, but that doesn't make them like Earth. It's as nonsensical as calling Jupiter a Super-Neptune, or calling Titan a Super-Pluto. You are selling out this encyclopedia with this compromise in principle and I will have to go the way of some professional astronomers, just as Dr._Submillimeter did, and "depart Wikipedia."
PLEASE CONSIDER this alternative:
"A popular misnomer for a Terrestrial planet that is larger than Earth but smaller than Uranus."

(e) There's a lot more I'd like to say but instead I'll refer you to here [[3]]

(f) Lastly, I'll stop refering to facts and reality, I get it now, facts and reality have no place here if they don't have proper references.
GabrielVelasquez (talk) 05:56, 5 January 2008 (UTC)

b. We know little enough about how our planet formed, so how can we speculate about the formation of planets outside our solar system? It could be stars themselves with their own characteristics (including metallicity and size) or their natural histories dictate. We have no good model of what sorts of planets should form around a dwarf star of spectral categories F, G, K, or M.

c. One should reasonably assume that any star not likely to have gone into a destructive phase within the time in which the star's light reaches us. Excessive caution might force people to assume that a main-sequence star such as Sirius might have exploded in a supernova event (even though a star the size of Sirius does not go supernova) or met a destructive collision in the time between a few years ago and now. One might not be so sure with a larger star such as Betelgeuse or Deneb much farther away. Unless one has cause to believe that what appears true of a star now visible is no longer true, then one must take the approach that what one sees of a normal star a few hundred light-years away is still true.

d. Of course I would expect a planet with a mass decidedly larger than that of Earth to have different characteristics, including the sorts of gases that its atmosphere could hold. A super-Earth about as cool as the Earth might have a helium-rich atmosphere but little uncombined hydrogen. Rough atomic weights for some of the most common gases in the universe are hydrogen (2), helium (4), methane (16), ammonia (17), water vapor (18), neon (20), carbon monoxide (28), nitrogen (28), oxygen (32), argon (40), and carbon dioxide (44).

Venus and Mars, planets smaller than the Earth but with very different temperatures, have atmospheres rich in nitrogen and carbon dioxide -- but practically no water vapor. Earth's atmosphere can hold methane and ammonia (although both are thermodynamically unstable in the presence of free oxygen) and of course free oxygen -- but not helium or hydrogen. Could a planet have a stable atmosphere rich in helium but not hydrogen? Would its greater pressure itself create a temperature too high for complex life as known on Earth?

--Paul from Michigan (talk) 04:15, 1 June 2009 (UTC)

c. Red dwarfs can't go supernova. If even the effects of gravitation, forces, explosions, etcetera on our planet travels at the speed of light then one has to talk of these things as they appear. Speculating on whether Betelgeuse has gone supernova for example, while fun, is sort of like speculating on what the inevitable pipeline will bring in the future, just like imagining what the words in the article 2037 in long-period comets will be, and too much of it gets to be pointless after awhile. According to the methods of science, is not fact, and therefore doesn't exist, until we observe it. And at any rate, the possibility of any single star not existing in 20 years is, with few exceptions, very small.. The shortest star lifetimes outlast the history of astronomy hundreds of times over. Red dwarfs will outlive the Sun.

b. Even the Earth has enough gases left locked up in it's rocks to fill up the atmosphere a hundred times over. Look at Venus. It makes no sense. Maybe it's very history-dependant, whatever numerous, non-easily observable from interstellar distance things that happened by chance influenced the current state of planets/systems a great deal, as much as we'd like a spreadsheat using like 5 simple quantities, each cell containing a neat class (warm sub-Neptune) complete wirh evolutionary backstory. Or maybe not always. Science will never be advanced if people don't look for relations and things tying things together. NGC 2009 10:27, 1 June 2009 (UTC)

I agree the term super-Earth is being stretched too far in the high-mass direction. Really, 10x Earth?? NGC 2009 10:32, 1 June 2009 (UTC)

Other notable planets

In 2011, the density of 55 Cancri e was determined. It is currently the largest Super Earth with a solid surface.

In 2014, the densities around Kepler-51 were announced. Although the outermost planet's mass is in the range of Super Earth's, its size is larger than Saturn's. --Artman40 (talk) 10:08, 21 April 2014 (UTC)