Naming Convention for Planets. What do you think?

[Deltafang]

While "planimals" are a possibility, "plants" and "animals" are restricted to Earth in the technical sense. Alien kingdoms of life could have primarily traits of animals, plants or fungi however. Or totally alien traits. It's quite possible that planets are filled with many forms of complex life, but such life is either sessile or semi-sessile and primitive (Such a world would be rather boring, however, unless you had some time-lapse cameras).

Agreed. A world filled with stationary life would be pretty boring. It might be hard for them to live through intense flares that way though. I remember in the game, Mass Effect, one of the alien races and the majority of that race's home planet species metabolize metals and keep them in the skin to protect themselves from their red dwarf sun. (Not too sure about the plausibility of that.) Could you imagine a planet that had sentient sessile life? That would be awkward. Well, for us at least. >_>;

Evidence suggests that Gliese 581d actually has no land at all, due to it's large size and possible origin beyond the "frost line" of it's system. So it would likely have a worldwide ocean hundreds of kilometers deep, with some interesting forms of pressure-induced water ice at the bottom.

Providing that nutrients could somehow reach the euphotic zone, there could be some life. It might be rather sparse though; biodiversity would be low.

I suppose "solid" "ground" could exist in the form of ice packs or bergs (perhaps possible at the poles, especially during winter) or rafts of colonial organisms.

Hmm, I was afraid of that. Its not necessarily a problem. Icebergs and floating packs of ice would be sufficient enough. Some life could possible evolve to crawl out of the water and onto ice rafts, especially if they were large and deep enough.

The atmosphere would also be pretty thick, so flying organisms could easily evolve from swimming pelagic ones.

That is definitely an interesting idea.

The high eccentricity of the planet would also result in pronounced seasons. The rotation would probably be similar to Mercury, and calculations done by RisingFury apparently show that 581d could be tidelocked (although I somewhat doubt it due to the eccentricity).

Tidelocking could be interesting as well. The night side could be entirely covered in a thin glacial sheet that breaks and travels across the globe before melting. If I decide to work with life on a moon, tidelocking still isn't necessarily a problem as a 'day' in terms of sunlight would still occur on both sides as the moon revolved around its planet. Though there could be darkness or light for long periods of time on either side depending on the speed of its revolution.

581d could indeed be an ice giant, since the detection method used only gives the minimum mass and the real mass could be far higher.

A moon of an ice-giant 581d might be a possibility, although I doubt that a large enough moon would be able to form around it.

That's a disappointment. If I planned to use a moon, I had my heart set on a high density moon in between Mars and Venus in size orbiting an ice giant for some reason. Thinking back, I'm not sure why. It just seemed like such a unique idea.

I'm liking the idea of an ocean planet more and more though.

Until we ran out of dead, unique religions, we might. Live religions might cause controversy (for example, I'd be uncomfortable with a planet called Yahweh or Jesus, a Muslim would probably be uncomfortable with a planet called Allah). Then again, that can vary a great deal even within a given religion, and names from current religions might be assigned out of religious fervor ("Jesus" is a common name in Spanish speaking countries, the Spanish named an island Trinidad "Trinity", etc.). Also expect the names of places from history or mythology, such as "Shangri-La" (I've seen this used a few times in Sci-fi), "Elysium", "Asgard," or, for places nobody wants to visit "Sheol", "Tartaros", etc.

Yeah, still active religions might end up pissing off alot of people and I'm not entirely comfortable with doing that either.

Names of places in mythology sounds like a good idea too. Very clever. Sheol and Tartaros sure have a forewarning ring to them. In context of course.

Thanks for all the help again guys. Its great to see such an active and helpful community! :thumbup:

 

[T.Neo]

Agreed. A world filled with stationary life would be pretty boring. It might be hard for them to live through intense flares that way though. I remember in the game, Mass Effect, one of the alien races and the majority of that race's home planet species metabolize metals and keep them in the skin to protect themselves from their red dwarf sun. (Not too sure about the plausibility of that.) Could you imagine a planet that had sentient sessile life? That would be awkward. Well, for us at least. >_>;

I suppose it could retreat into a resistant shell of some kind. Like how a venus flytrap closes, but a defence mechanism.

Sapient sessile life wouldn't be possible if the organism lacked a nervous system of some kind, and even if it did there would be little reason for the organism to be so intelligent.

Hmm, I was afraid of that. Its not necessarily a problem. Icebergs and floating packs of ice would be sufficient enough. Some life could possible evolve to crawl out of the water and onto ice rafts, especially if they were large and deep enough.

Well, I'd imagine it would be a means of getting away from predators temporarily. But I doubt organisms would evolve to live on the icepacks or rafts permanantly (although flying creatures might roost there).

Tidelocking could be interesting as well. The night side could be entirely covered in a thin glacial sheet that breaks and travels across the globe before melting. If I decide to work with life on a moon, tidelocking still isn't necessarily a problem as a 'day' in terms of sunlight would still occur on both sides as the moon revolved around its planet. Though there could be darkness or light for long periods of time on either side depending on the speed of its revolution.

Well, as I said, 1:1 tidal locking might not happen due to the eccentricity.

A moon would probably have a longer rotational period then the Earth (due to being tidelocked to the parent planet) but it might be on the order of a few days at most. If it's orbiting an ice giant especially, it will need to orbit close to be stable.

Day-night temperature swings on such a moon would depend on both the rotational period and the thickness of the atmosphere.

I've heard that the minimum mass for a habitable moon is around 0.3 Earths (still bigger then Mars).

That's a disappointment. If I planned to use a moon, I had my heart set on a high density moon in between Mars and Venus in size orbiting an ice giant for some reason. Thinking back, I'm not sure why. It just seemed like such a unique idea.

Well, maybe it could happen, but the chances are low. The figure of 0.3 Earth masses is between Mars and Venus, but I don't see what would be special about density other then the uniqueness factor.

Sheol and Tartaros sure have a forewarning ring to them. In context of course.

Perhaps for Gliese 581e and Gliese 581c respectively? Both are places one would rather not set foot on.

 

[Ghostrider]

Until we ran out of dead, unique religions, we might. Live religions might cause controversy (for example, I'd be uncomfortable with a planet called Yahweh or Jesus, a Muslim would probably be uncomfortable with a planet called Allah).

What do Hindus think? Their pantheon comprises some 330000 devas (avatars of the Supreme Being, don't shoot me I'm no theologist). More than enough for our needs...

 

[Linguofreak]

Names of places in mythology sounds like a good idea too. Very clever. Sheol and Tartaros sure have a forewarning ring to them. In context of course.

Actually Sheol is a term from a still-extant religion, and even Tartaros shows up as a word for "Hell" in Christian writings at times, but I think religious place names tend to be a bit less controversial than religious personages for such things. Calling a planet "Eden" or "Hell" doesn't strike me as being as sacrilegious and weird as calling it "Jesus" or as plain weird as calling it "Satan".

 

[Deltafang]

Well, I'd imagine it would be a means of getting away from predators temporarily. But I doubt organisms would evolve to live on the icepacks or rafts permanantly (although flying creatures might roost there).

In this imagined ocean world, you said the atmosphere could be thick enough for flying creatures to exist. Since its an ocean world, I'd imagine they'd swim or float across the surface as well. As for escaping predators on the ice floes, it could also be a way to reproduce safely before returning to the water.

For some reason, I keep imagining some kind of warped alien seagulls, seals, and tortoises. :lol:

Well, as I said, 1:1 tidal locking might not happen due to the eccentricity.

A moon would probably have a longer rotational period then the Earth (due to being tidelocked to the parent planet) but it might be on the order of a few days at most. If it's orbiting an ice giant especially, it will need to orbit close to be stable.

Day-night temperature swings on such a moon would depend on both the rotational period and the thickness of the atmosphere.

I've heard that the minimum mass for a habitable moon is around 0.3 Earths (still bigger then Mars).

Hmmm, a close orbit? I don't remember hearing anything about the radiation in proximity with an ice giant. I'd assume it'd be the same or close to normal gas giant of similar size. The native life forms of such a moon would probably have some kind of protection against both the planet's radiation as well as the star's.

I still need to work out a rotational period and atmospheric thickness for it. How thick would it have to be to have what could barely be described as "even heating"? (Compared to Earth's atmospheric statistics that is)

Well, maybe it could happen, but the chances are low. The figure of 0.3 Earth masses is between Mars and Venus, but I don't see what would be special about density other then the uniqueness factor.

So a moon with 0.5 - 0.6 Earth masses would be kinda heavy for an ice giant to be dragging around, huh? Sorry about the density, I assumed it'd be able to hold on to an atmosphere better if it was denser for its size. How close or far would that have to be to retain a stable orbit if its even capable of that. In that case, would that make it a binary planet? Could you even imagine that? A Uranus-like planet in a binary relationship with something slightly smaller than Earth? I started thinking about that in class today. (completely ignored the lecture)

I think you said that some of the Super-Earths we've found could possibly be Hot Neptunes based on mass, right? What if there was a Super-Earth/Hot Neptune binary planet? Could such a thing even exist? Would they be tide locked if they could maintain a stable orbit?

As for naming, I think I'm going to name the planets after either locations in the Greek Underworld or the rivers there. Sounds dark and mysterious. :thumbup:

 

[Linguofreak]

What do Hindus think? Their pantheon comprises some 330000 devas (avatars of the Supreme Being, don't shoot me I'm no theologist). More than enough for our needs...

I don't know what the Hindus think. As I said, there's a fair bit of variation even in Christian cultures. The Spanish were quite free about giving names to ships and places that make Protestants very uncomfortable when translated, such as the "Holy Trinity and our Lady of Buen Fin", which basically means they were calling a ship "God and Mary". And, as I mentioned, Spanish speaking cultures will still freely name their kids "Jesus", although to be fair, "Jesus" is just the Greek form of Jesus' name (Yeshua), and it was fairly common around that time. Basically "Joshua". There is in fact a sorcerer by the name of Bar-Jesus mentioned in Acts, of no relation to Jesus, and a Christian mentioned in Colossians by the name of "Jesus who is called Justus". In fact, early texts have Barabbas, who the Jews demanded released when Pilate offered to release Jesus, as also having had the first name "Jesus".

 

[natey787]

I thought about naming extrasolar planets before, actually. I thought it wouldn't make sense just yet, but once we start finding habitable worlds, ones which someday (sigh) we might be able to visit, I think it would be cool to name them after fictional planets in Sci/Fi. How cool would it be to go to a planet called Coruscant, or Arrakis, Trantor, or Hoth? That is, if future scientists will still read the science fiction classics.

 

[T.Neo]

For some reason, I keep imagining some kind of warped alien seagulls, seals, and tortoises. :lol:

Well, considering the environments they're in (aquatic, semiaquatic, aerial) they could probably have a strong resemblance to organisms in similar environments. They probably won't be seagulls, seals or tortoises in the literal sense though.

Hmmm, a close orbit? I don't remember hearing anything about the radiation in proximity with an ice giant. I'd assume it'd be the same or close to normal gas giant of similar size. The native life forms of such a moon would probably have some kind of protection against both the planet's radiation as well as the star's.

AFAIK, ice giants are the "mini" variety of gas giants. Once they get abouve a certain size they just keep on accreting and accreting hydrogen. Jovian planets have mantles of metallic hydrogen, Neptunian planets have mantles of water and other volatiles.

Not sure about the radiation production of the parent planet, but provided the moon has a thick enough atmosphere, strong enough magnetic field or both, it should not be a problem. It's useful to factor in potential radiation resistance that local life would probably have.

So a moon with 0.5 - 0.6 Earth masses would be kinda heavy for an ice giant to be dragging around, huh? Sorry about the density, I assumed it'd be able to hold on to an atmosphere better if it was denser for its size. How close or far would that have to be to retain a stable orbit if its even capable of that. In that case, would that make it a binary planet? Could you even imagine that? A Uranus-like planet in a binary relationship with something slightly smaller than Earth? I started thinking about that in class today. (completely ignored the lecture)

It might be.

A Neptunian-Superterrestrial binary planet might work, as might a neptunian with a sub-Earth mass terrestrial satellite.

Not sure about the ability to hold an atmosphere; I'm of the impression that mass and insolation are what count, not density.

Members of a binary planet would probably both be tidelocked to eachother (although it would depend on the specific system of course).

 

[Linguofreak]

How can we expect even what is plausible and what is not, not having a slightest idea what life is, much less what is intelligence?
For what we know, there can be anything on distant stars, from life made out of distinctly different chemistry and concepts to pretty much the same humans we have here.

---SNIP---

Or, they could be a ball of intelligent plasma orbiting a star.

Well, we can tell that certain things are more likely than others. The ball of intelligent plasma is unlikely, because we don't know of any way that the plasma could be formed into information-bearing structures, whereas with solids with liquids mixed in, the capability for such structures is obvious.

As for intelligence, it's all relative- a human is more intelligent then a cow, a flatworm more intelligent then a mushroom.

Assuming that there is no such thing as a "soul" and that the human mind is solely a data structure on a computational device (the human brain and hormones) that exists entirely within this universe, yes. Intelligence can then be defined as raw computational capacity and speed, although then it would still need to be measured for different fields of computation: The human brain outstrips any computer in stuff like pattern matching, but any pocket calculator can do better for simple integer arithmetic.

There are many who would do not hold the above assumption, however, myself included.

As for humans evolving elsewhere, it's complete and utter rubbish. Our evolution took too many turns to be repeated elsewhere in the universe. Even on our own world, life radiated into a myriad of forms of which we are only one. And vertebrates are themselves limited to Earth; analagous organisms elsewhere will probably only be similar to vertebrates on a superficial level.

Well, I generally would agree, although there are possibilities that have showed up in sci-fi that wouldn't be altogether out of the picture, although I put pretty much zero stock in any of them.

If the Greys have been abducting people for a few thousand years and have an FTL drive, there could be humans on every planet across the galaxy by now. (Yeah right).

If any deity is involved in the mix, then practically anything can happen. God would have to have a fairly small imagination to populate every suitable planet with the same biosphere, but I could imagine it being done just for fun and to see how the humans react when they encounter an exact copy of Earth sitting somewhere in the Large Magellanic cloud.

And, of course, you can never tell *what* the Magratheans are going to do. (42 exact copies of Earth, anyone?)

For the last time in the study of life; NO OTHER HUMANOIDS.

Depends what you mean by "humanoid". By a stretch, the praying mantis could count as humanoid.

I will agree that the typical sci-fi humanoid, complete with be-mammaried females endowed with the same number, size, and location of the organs in question as humans (something which we don't even share with something as closely related to us as the cow, the platypus, or the shark), is something we're unlikely to find anywhere else.

 

[sputnik]

First person to land on it, or orbit it where landing isn't possible, gets to name it.

There's your naming convention....

 

[Linguofreak]

Well, maybe it could happen, but the chances are low. The figure of 0.3 Earth masses is between Mars and Venus, but I don't see what would be special about density other then the uniqueness factor.

Well, for a given mass, a higher density will have a higher escape velocity (the cutoff point is around 8 km/s for holding an atmosphere for billions of years), a higher surface gravity, a lower surface area* (and thus slower heat dissipation and the interior staying molten longer), a bit more heat going in when the planet forms (the higher escape velocity for a given mass means impactors hit harder), etc.

Of course, it probably won't be much denser than iron (though you will get gravitational compression), and a too-high-iron body might have chemical constraints on habitability.

*Lower per unit mass, greater per unit volume.

 

[T.Neo]

Assuming that there is no such thing as a "soul" and that the human mind is solely a data structure on a computational device (the human brain and hormones) that exists entirely within this universe, yes. Intelligence can then be defined as raw computational capacity and speed, although then it would still need to be measured for different fields of computation: The human brain outstrips any computer in stuff like pattern matching, but any pocket calculator can do better for simple integer arithmetic.

Raw computational power isn't what I meant. I meant the things the organism does with that computing power- formulating concepts and ideas etc. If you had a computer with many times the power of the human brain, it could be doing nothing more then crunching numbers and thus not be sapient.

And why should the concept of soul be limited to sapient life?

Well, I generally would agree, although there are possibilities that have showed up in sci-fi that wouldn't be altogether out of the picture, although I put pretty much zero stock in any of them.

There is no physical law preventing humanoids, it's just that the human form is highly, highly unlikely to be repeated elsewhere.

If the Greys have been abducting people for a few thousand years and have an FTL drive, there could be humans on every planet across the galaxy by now. (Yeah right).

Depends on the speed of your FTL drive. :lol:

If they had Orion-type pulse propulsion spacecraft, and abducted a sizable amount of humans during prehistory, there could be populations of humans strewn across nearby space.

If they had more advanced (think Project Valkyrie) travel methods, there could be populations of humans over a far wider area.

This of course is not counting the fact that humans will probably have trouble surviving on local foodstuffs, etc.

If any deity is involved in the mix, then practically anything can happen. God would have to have a fairly small imagination to populate every suitable planet with the same biosphere, but I could imagine it being done just for fun and to see how the humans react when they encounter an exact copy of Earth sitting somewhere in the Large Magellanic cloud.

Regardless of whether there is an entity involved, we have a pretty good grasp of the laws of nature- things don't just appear on a whim.

And as I said earlier, there isn't any law preventing an exact copy of Earth from existing, it's just that it is highly, highly unlikely.

And, of course, you can never tell *what* the Magratheans are going to do. (42 exact copies of Earth, anyone?)

Identical right down to the fjords. :rofl:

Depends what you mean by "humanoid". By a stretch, the praying mantis could count as humanoid.

I will agree that the typical sci-fi humanoid, complete with be-mammaried females endowed with the same number, size, and location of the organs in question as humans (something which we don't even share with something as closely related to us as the cow, the platypus, or the shark), is something we're unlikely to find anywhere else.

You have raised a good point. When I refer to "humanoids" I am generally referring to the latter.

There could indeed be organisms that are pillar-erect bipeds like humans. We in fact know of one such group of animals right here on Earth- penguins.

 

[Deltafang]

Once they get abouve a certain size they just keep on accreting and accreting hydrogen. Jovian planets have mantles of metallic hydrogen, Neptunian planets have mantles of water and other volatiles.

Not sure about the radiation production of the parent planet, but provided the moon has a thick enough atmosphere, strong enough magnetic field or both, it should not be a problem. It's useful to factor in potential radiation resistance that local life would probably have.

Yeah, I agree. The local life would have to evolve some sort of radiation protection in any case. Either against the planet's radiation, or the sun. Do you think the metallic hydrogen would have anything to do with intense radiation belts? But if the moon is geologically active with a strong magnetic field, it'd be a bonus I think. Both the moon and the planet's magnetic field protect it from the star and the moon's own field protects it from its parent planet.

A Neptunian-Superterrestrial binary planet might work, as might a neptunian with a sub-Earth mass terrestrial satellite.

Hmmm, what an interesting concept! Are we clear on what constitutes a binary planet yet? I mean, size ratio and/or barycenter wise. Our definition is probably going to change in the future as we haven't really decided on what defines a 'doubly planet' yet. Likewise, we know how much mass it takes to become a brown dwarf or a star, but I haven't been able to find classifications of how much mass it takes to become an gas or ice giant. (ice giants being smaller versions of gas giants) What exactly is the lower mass limit?

Alright, say a terrestrial planetary body of about 0.73 Earth masses was orbiting the barycenter of itself and a neptunian planetary body of about 6-8 Earth masses. That sound feasible? (Uranus has a mass of 14.5 Earth masses.) EDIT: I see on the wikipedia article for cold neptunes that the definition for one is about 10 Earth masses to a little less than saturn.

Hmmm, that's interesting I guess. So anything less than 10 Earth masses wouldn't be considered "giant"? Would that then be considered a Superterrestrial planet with a super thick atmosphere? I wonder if 10 masses is the minimum for water, ammonia and methane accretion in large amounts. I'm sure we don't know yet, but I'm a big fan of "hard" sci-fi aspects and I like to make sure many if not all things check out.

I'm a big fan of Uranus' coloring as well. So an ice giant half of Uranus' size and mass with similar coloring and perhaps a few color variation bands and storms would be nice.

Members of a binary planet would probably both be tidelocked to each other (although it would depend on the specific system of course).

Hmm. Tidelocking isn't necessarily a problem overall. If they were close enough to their star and depending on the specifics of their revolution around the barycenter, the smaller terrestrial one with the thick atmosphere could easily have 'days' and 'nights'. The Neptunian planet could also eclipse the star on occasion.

The only problem I see is that ice giants usually form behind the frost line, which is pretty damn far in our own solar system. It might be proportionally smaller in a red dwarf system, but how would a Neptunian planet get into the habitable zone? What could cause it to migrate and what effects would it have on the planet itself? Since the hydrogen compounds and volatiles form solid grains past the frost line, what would happen if it were to move into the habitable zone? I'd imagine the ice grains would would start to melt and the volume would gradually increase slowly but surely turning it into a less dense Hot Neptune. What do you think?

A few more questions. As I approach the final statistics for this binary planet (the one with life on it would of course be the one I spend the most time one!) let's assume that the terrestrial planet is 0.73 Earth masses and the 'warm' neptune() is roughly 6.8 Earth masses (could increase based on what I learn about definitions of 'giants', I heard someone use the term 'gas dwarf' recently. I suppose there could be an 'ice dwarf' then). What distance would this hypothetical binary planet be away from each other and is it unimaginable to have a close to symmetrical barycenter between the two? How stable could the orbits be? (around both each other and their sun) Would they last long enough form life to form? (By our standards and timescales)

Lastly, I think I've decided that the solar system naming convention will be based on Greek Underworld geology. Just got to work on assigning them. I also added a hypothetical Gliese 581 f to the system which is nothing more than your standard Class I gas giant. Maybe perturbations from this gas giant's elliptical orbit could have slowly moved Gliese 581 d (my neptunian ice giant) into the inner system where it eventually finds it way into orbit around Gliese 581 g (the newly found dwarf-Earth).

Yeah, that sounds a bit confusing. Let me try to clarify. How about this: we basically assumed that Gliese 581 d is a Super-Earth due to its mass, but its actually a Cold Neptune that migrated into the habitable zone. Gliese 581 f was found shortly afterwards as a distant gas giant. The last planet found was Gliese 581 g which was found to be in a binary planet with Gliese 581 d. For those that don't know, Gliese 581 e is the closest planet to the parent star in the system. Its also the most recent one found. (In my future we find both f and g) Hope that simplifies it a bit.

Oh, yeah. Since this has gotten a bit off topic and I've found a naming convention that works, do you all think I should start a new topic on the mechanics of a habitable solar system or do we continue it here?

Thanks again for all your help! Keep it up, this is incredibly interesting! :thumbup: So much so that I zone out in class while thinking of different possibilities for this solar system. :lol:

 

[KKinsane]

THE simplest naming convention i've seen goes, star name, star name add roman numeral for each planet by relative distance to the star, and for moons A B C etc

IE. alpha centuri IV-B, would be hypothetically the fourth planets second moon.

obviously you have to explore the place first and establish just what is there, I'm sure we haven't missed anything we can class as a planet in this solar system but if we used this naming convention and found a planet inbetween the ones we know of it would throw all your data out of whack for a while at least, and normally planets can get personal names depending on their character once more is known of them. did we run out of greek gods or something? like particle physics nearly ran out of greek letters?

also this may interfere with such things as M-31, sagitaruis A* if you get me, galaxy naming convention I think, in that particular case they are believed to be the locations of gravitational anomolys which I refuse to acknowledge are holes in spacetime itself. either way I think its a pretty useful way to list out a new system on the ol' scanners before you visit the places, if only we had warp drive...and some pretty sick scanners...

 

[T.Neo]

The star should not produce prohibitive amounts of radiation. The atmosphere alone would be enough to shield life on the surface from stellar radiation.

The most popular definition of binary planet I've seen is where the barycenter is above the surface of both bodies. The classification of double planet is mostly an informal one, however.

Ice giants can be seen as a bridge between terrestrial planets and gas giants; ice giants are ocean worlds, like Gliese 581d is thought to be. It's just that they have very thick hydrogen rich atmospheres.

At 6.8 Earth masses, it will probably be a super-Earth with extensive or worldwide oceans. It could have global cloud cover however, but it'll likely be white water clouds and not greenish-blue methane haze.

I don't know whether it would be stable though. Perhaps, if tidal effects from Gliese 581 are not prohibitive.

THE simplest naming convention i've seen goes, star name, star name add roman numeral for each planet by relative distance to the star, and for moons A B C etc

In reality it works the other way around; planets are named alphabetically starting with b, and moons are named by roman numerals.

 

[Deltafang]

The star should not produce prohibitive amounts of radiation. The atmosphere alone would be enough to shield life on the surface from stellar radiation.

Noted.

Ice giants can be seen as a bridge between terrestrial planets and gas giants; ice giants are ocean worlds, like Gliese 581d is thought to be. It's just that they have very thick hydrogen rich atmospheres.

At 6.8 Earth masses, it will probably be a super-Earth with extensive or worldwide oceans. It could have global cloud cover however, but it'll likely be white water clouds and not greenish-blue methane haze.

Yeah, I thought as much. I was reading the wikipedia page on planetary formation as well as a few articles and they noted and seem to agree that ice giants are thought to be failed cores of 5-10 Earth masses that began accretion too late, when the other giants ate up all the gas. I've also heard a lot of the term "gas dwarf" lately.

This forum in particular has a thread on it: http://www.newmars.com/forums/viewtopic.php?f=57&t=8324&sid=9b93a08384c7c011a84e60dbfb27b646

I also found a picture of a gas dwarf that was uploaded to wikipedia but never used. People have used it as an example in other threads as well.
http://commons.wikimedia.org/wiki/File:Planet_Gas_Dwarf_Animated.gif

It seems an ice dwarf of similar color to the picture of around 7 Earth masses could exist, maybe.

The fact that it would have migrated to the inner solar system could have an effect on its structure and composition though. It could increase in volume and expand due to the heat, perhaps clouds could form that way too and the resulting insolation would heat it up enough for the top layers of the exotic ice core to melt. Maybe if we moved an ice giant into the inner solar system, it would result on it becoming a sort of semi-chthonian ocean planet where the outermost layers of hydrogen and helium are stripped away, leaving oceans and a dense atmosphere of different content. It would probably also create highly visible storms. I'd think the process would take quite a long time though. It could have 'just' migrated (on a stellar timescale).

I don't know whether it would be stable though. Perhaps, if tidal effects from Gliese 581 are not prohibitive.

Hmm, should we expect severe tidal effects from a red dwarf? I wonder. I think this whole idea of a Warm Neptune-Dwarf Earth is a little less than far fetched. I mean, it seems plausible enough. It might not remain stable for a long time though.

Do you think I should start a new thread for this discussion now as the topic has changed? Or is continuing it here fine?

 

[T.Neo]

Tidal effects from a red dwarf would depend on the distance to the star. It is lower mass then the sun, but it is still pretty massive and if you are close enough it will create tidal effects. Jupiter, for example, is a tiny fraction of the mass of the sun but it still has huge effects on it's moons.

Cloud formation depends on temperature. At Jupiter or Saturn like temperatures, ammonia clouds are predominant. At higher temperatures (Earthlike) water clouds will be predominant. Higher still, the planet would be within a temperature zone where no chemicals would condense to form considerable clouds, and the planet would be featureless and blue due to reyleigh scattering. Higher still, and the planet would be covered in worldwide sodium haze, and at temperatures over 1400K even silicate clouds could form.

Uranus and Neptune are not included in the Sudarsky model of planetary appearance, but their appearance is due to methane clouds and methane haze, AFAIK, which can only form at low temperatures at distances far from the parent star. Class III cloudless planets would probably be too close to their stars to be within the habitable zone, and class II planets will be whitish unless there are reddish or brown tholin or phosphorous condensates in their clouds.

I don't think there could be condensates at that distance which would make the planet blue. If the water clouds were low enough in the atmosphere, they might be partially obscured by the atmosphere and thus be bluish, but this is somewhat unlikely.

As you are the topic starter, I believe the decision to move the discussion or keep it here is yours.

 

[Deltafang]

Cloud formation depends on temperature. At Jupiter or Saturn like temperatures, ammonia clouds are predominant. At higher temperatures (Earthlike) water clouds will be predominant. Higher still, the planet would be within a temperature zone where no chemicals would condense to form considerable clouds, and the planet would be featureless and blue due to reyleigh scattering. Higher still, and the planet would be covered in worldwide sodium haze, and at temperatures over 1400K even silicate clouds could form.

How long do you think it'd take for a planet to change classes in the Sudarsky model? I'd think it would take hundreds of thousands to millions of years for a jovian to completely change.

Uranus and Neptune are not included in the Sudarsky model of planetary appearance, but their appearance is due to methane clouds and methane haze, AFAIK, which can only form at low temperatures at distances far from the parent star. Class III cloudless planets would probably be too close to their stars to be within the habitable zone, and class II planets will be whitish unless there are reddish or brown tholin or phosphorous condensates in their clouds.

Hmm, so a gas giant in the habitable zone would be a whitish Class II planet?

I don't think there could be condensates at that distance which would make the planet blue. If the water clouds were low enough in the atmosphere, they might be partially obscured by the atmosphere and thus be bluish, but this is somewhat unlikely.

As you are the topic starter, I believe the decision to move the discussion or keep it here is yours.

Awww. Like I said before, maybe it could be in the process of changing classes and therefore retain some of its banding or other color features when viewed from a distance.

I think I will start a new thread, we've gotten very off topic haha.:lol:

 

[T.Neo]

Unfortunately the change would probably be rather swift. Weather (even weather made of methane) is highly dependant on insolation. Temperatures in the upper atmosphere would probably change pretty quickly and due to that, methane and ammonia clouds would soon evaporate. The migration of the planet will also not be instantaneous.

A class II planet should be whitish, if it doesn't have condensates in the atmosphere. But they would likely be reddish or brownish like seen on Jupiter and Saturn.

A planet in the habitable zone might be class III (blue and featureless) if it had enough internal heating (i.e. far more massive then Jupiter) or even a class IV or V planet, although it would be in the range of being a brown dwarf for that to occur.

 

[Deltafang]

Unfortunately the change would probably be rather swift. Weather (even weather made of methane) is highly dependant on insolation. Temperatures in the upper atmosphere would probably change pretty quickly and due to that, methane and ammonia clouds would soon evaporate. The migration of the planet will also not be instantaneous.

A class II planet should be whitish, if it doesn't have condensates in the atmosphere. But they would likely be reddish or brownish like seen on Jupiter and Saturn.

Actually, I've just found something interesting. Increasing concentrations of methane, ammonia and water are found the deeper you get to an ice giant such as Neptune's core. The mantle is rich in these three. Neptune and Uranus have similar atmospheric methane content, but Neptune appears much more blue probably because methane is somehow escaping from the mantle. That could be a reason that my ice dwarf still has a bluish color. Though that would only be temporary until the mantle's supply of methane and ammonia completely evaporated.

I was thinking maybe the gas giant Gliese 581 f could have possibly played a part in its migration to the inner solar system. Gliese 581 b as a Hot Neptune probably either migrated itself. Even if it didn't, it probably accreted all the gas in the inner solar system, while Gliese 581 f sucked up most of the outer system gas. That would leave Gliese 581 d a gas dwarf.

A planet in the habitable zone might be class III (blue and featureless) if it had enough internal heating (i.e. far more massive then Jupiter) or even a class IV or V planet, although it would be in the range of being a brown dwarf for that to occur.

I meant to ask you about Class III planets. They're blue due to Rayleigh scattering and absorption of methane, right? They're relatively warm, but have methane in their atmosphere still. They exist very close though, probably much closer in than the goldilocks zone. I'd think the habitable zone for a red dwarf would produce some intermediate stage between Class II and III.

Unfortunately, the Sudarsky Extrasolar Planet Classification System doesn't apply for anything lower than roughly 20 Earth masses. (That means ice giants, ice dwarfs, and super-earths)

I've started a new topic for the discussion of this planetary system as this was originally about naming planets. Anyone who wants to continue this discussion can find it just above this thread.

Thanks again for all the help everyone, you've been too kind! Let's all keep up the good work!

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Names of planetary bodies in Gliese 581:

Gliese 581 - type M3V red dwarf
Gliese 581 e "Lethe" - Super-Earth - black and red molten surface
Gliese 581 b "Cocytus" - Hot Neptune - moderate axial tilt with bands of water clouds at northern pole and cloudy 'halo' around solar terminator
Gliese 581 c "Phlegethon" - Super-Earth - thick, translucent atmosphere with some surface features visible
Gliese 581 d(g) "Styx" - Ice-Dwarf - Ice Dwarf (mini ice giant) in the process of warming. Hazy hydrogen atmosphere with whitish-blue water clouds. In a binary relationship with Elysion.
Gliese 581 g(d) "Elysion" - Dwarf-Terrestrial - Ocean planet with white water clouds in the atmosphere. Ice caps, free floating icebergs, and black blotches visible from orbit. In a binary relationship with Styx.
Gliese 581 f "Archeron" - Class I gas giant - standard hydrogen/ammonia gas giant