Is Pluto a planet?

[WestAir]

On 10/13/2020 at 1:51 AM, K^2 said:

Pluto definitely can't be a planet or we'll have like a dozen more we'll have to add.

Moon, on the other hand, totally a planet. It's silly that we count it as Earth's satellite, when Sun pulls on it a lot stronger than Earth does. Moon orbits the Sun and happens to share the orbit with Earth. So we should bring the count back to 9, with Earth-Moon system counted as a binary.

I know, I know, some people might complain that Moon not being a moon would get confusing. But if Moon is reclassified as a planet, it would need to be promptly renamed after a Roman deity, and honestly, the only sensible choice is to call it Luna. So that should resolve the confusion. Well, in English. Other languages will have to find their own workarounds.

P.S. I have one final argument. If we say that Moon/Luna is a planet, humanity is technically an interplanetary civilization.

This is hands down my favorite post in this entire KSP forum.

[Space Nerd]

I think a large moon should be considered both a moon and a planet. (I think "satellite planet" is a good word for it.)

And this also solves the "it's a moon or binary planet" problem.

Although I think if a system's barycenter is in empty space at least part of time then the companion object should not be considered a moon.

[kerbiloid]

Actually, what's the problem with having > 8 planets except the school teachers who are used to ask "How many planets are there in Solar System?.. Now list them all..." ?

99% of people unlikely remembers even 8.
1% of nerds anyway can recall several tens.
Astrologists are anyway happy with their own classification.

[SOXBLOX]

Trying to draw lines between balls hanging in space where nature itself draws no lines is an endeavour bound to end badly, I guess. Fortunately, there are some obvious differences. We can divide stars and stellar remnants from planets by defining stellar objects as bodies which sustain fusion, or did sustain fusion in the past. Hydrostatically rounded non-stellar objects are distinct from non-round ones; we can divide asteroids, minor moons, and comets from...round things.

Now for dividing the round things further. The first obvious difference would be between objects which orbit the center of a star system and those which do not. But, as @K^2 pointed out, "moons" and "planets" both orbit the star, which is the dominant gravitational influence on each of them. The only difference between them is that one's solar orbit is a little bit "wobblier" than the other.....aaaand, we're back at the barycentercentric (pardon) definition of "moons" and "planets". It's a nice definition, but to make it precise enough to be useful, it has to be complex, which means it is probably a poor definition.

Should we simply divide at an arbitrary ratio of masses, and leave out the barycenter? Then moons would be anything orbiting the parent below this fraction of their parent's mass, and double planets would be those with companions above this fraction. Or should we just call all moons and the seconds of double planet systems "companions"? IDK.

Now we have to divide between the hydrostatically rounded objects which do not orbit an object besides the central star of their system. We could use arbitrary size or mass values, but those would be arbitrary. (Duh!) There are some obvious (nonphysical) differences between objects orbiting in or near the ecliptic plane and those orbiting at high inclinations to it, and those with nearly circular orbits and those with highly eccentric ones. Let's draw a line there. Objects with less than, say, 0.5 eccentricity and which deviate from the ecliptic plane by less than 20° are major planets, and the others are oddballs.

Can we divide the oddballs further? I don't think so, but it would be helpful to, especially in the case of an oddball gas giant in the middle of a bunch of Sedna clones. Any ideas? Maybe oddball major planets and oddball minor planets, with an arbitrary size division?

Edited October 15, 2020 by SOXBLOX

[Entropian]

7 hours ago, kerbiloid said:

Every moon orbits the Sun (in/on/by/?...) epicycloid trajectory.

"on an epicycloid"

7 hours ago, kerbiloid said:

'Oumuamua orbits the Sun (in/on/by/?...) hyperbolic trajectory.

in/on, but not by.

[sevenperforce]

17 hours ago, NFUN said:

18 hours ago, sevenperforce said:

That seems like saying "I see no benefit to calling all miniature horses, horses."

Miniature horses are horses. It's right there in the name.

this isn't how loveing language works. This is the worst argument and everybody who makes it should feel embarassed

While I take no offense, I'm also unembarrassed. This is exactly how language works. Not trying to pull rank or anything, but in English common parlance, lexemes formed by open compounding, using a modifying dependent along with a noun, strongly imply that the thing being identified is a subset of the group represented by that noun. Fighter jet, writing desk, compact car, pickup truck, potted plant, garage door. These are all endocentric compounds, where the adjectival dependent modifies and restricts (but does not alter) the meaning of the obligatory head.

Endocentric compound lexemes should be distinguished from ordinary noun phrases, like "the brown desk" or "a small horse" where the adjective denotes a characteristic without defining a subclass.

It is true that we have lexemes in which an open compound (with the adjective+noun structure) is used to denote a new class rather than a subclass. These are exocentric constructions. A red head is not a particular type of head, for example, and a bird house is not a subclass of (the common usage of) houses. But such constructs are the result of evolution and fixation of the lexeme within a dialect, not prescription. If one of our goals in sharing science is to make science accessible to the public, we shouldn't deliberately choose a nomenclature where a modifier+noun combination denotes a new class rather than a subclass. It's inherently confusing.

To borrow one of the examples above, it would be like saying, "Oh, we don't call any land masses islands anymore. We call them dwarf continents. But a dwarf continent is not a type or subclass of continent." That would be ridiculously confusing.

17 hours ago, K^2 said:

You keep making the definition more and more complex. "A body is a moon if and only if there exists another body qualifying as planet or dwarf planet, such that the barycenter of the two is on a quasistable trajectory entirely contained within the surface boundary of the later." This sounds like a theorem from convex geometry. When your definitions for categories start to sound like that, you have a bad taxonomy. All just to try and squeeze the Moon into a definition of the moon.

First, you're overspecifying for effect.

Second, the point is to identify a binary. "Binary" should be applicable beyond the moon-planet division, and it should be applicable without reference to an external attractor. What about rogue planets? There's no star to deal with, there. A rogue planet is a binary system if the barycentre is ever in free space and it is a satellite system if the barycentre is not ever in free space. You don't need to reference any third body. It doesn't matter what orbit you're in.

Or you can define it the other way, if you prefer: a system is a binary system if the barycenter is always in free space and it is a satellite system if the barycenter is ever under the surface of either body. That way you avoid questions about whether Sol+Jupiter is a binary system. This definition applies to asteroid binaries and planetary binaries and stellar binaries and black hole binaries (and even galactic binaries, with a little nudging). It's universally applicable.

14 hours ago, Superfluous J said:

I'm not sure Ceres and Pluto should be in the same category. I'm not sure why it's so bad to call Ceres an asteroid.

Because Ceres is a world. It is gravitationally rounded. It's also large enough to have significant influence on objects which share its orbit. It has approximately fifty trojan asteroids.

And if Pluto was where Ceres was, it wouldn't be a planet either. It's not large enough to clear the asteroid belt.

9 hours ago, NFUN said:

the fact jupiter has trojans is evidence it does dominate its orbit. and i'm not sure how a gas planet could even fail to be in hydrostatic equilibrium, but you do you

Evidence, yes, though not sufficient evidence. Ceres has trojans too. That's why I would prefer a definition like "the mass it exerts resonant influence on is greater than half the total mass that crosses its orbit."

But yeah obviously a gas giant is in hydrostatic equilibrium. It doesn't have a surface.

5 hours ago, Space Nerd said:

I think if a system's barycenter is in empty space at least part of time then the companion object should not be considered a moon.

This was my initial impulse but on reflection I think the rule should be "all of the time". Otherwise you run into the question of whether Jupiter and the Sun are a binary.

2 hours ago, SOXBLOX said:

we're back at the barycentercentric (pardon) definition of "moons" and "planets". It's a nice definition, but to make it precise enough to be useful, it has to be complex, which means it is probably a poor definition.

It's easy to make it precise. If the barycentre ever dips beneath the surface of the larger body, it is a satellite system. If it never does, it's a binary system. Applies to stars too.

2 hours ago, SOXBLOX said:

Objects with less than, say, 0.5 eccentricity and which deviate from the ecliptic plane by less than 20° are major planets, and the others are oddballs.

Can we divide the oddballs further? I don't think so, but it would be helpful to, especially in the case of an oddball gas giant in the middle of a bunch of Sedna clones. Any ideas? Maybe oddball major planets and oddball minor planets, with an arbitrary size division?

This is where solar system formation tends to help us out, I think. Very large objects with very inclined orbits are very likely to get themselves ejected.

But it also signals that we need to think about separating intrinsic descriptors from extrinsic descriptors. Calling something a "giant planet" or a "world" or a "planetoid" describes its intrinsic qualities. Calling something a "moon" or a "major planet" or an "irregular planetoid" describes its extrinsic qualities. You can cross-combine these descriptors without difficulty. For example, you could have an irregular giant planet.

[kerbiloid]

20 hours ago, sevenperforce said:

That seems like saying "I see no benefit to calling all miniature horses, horses."

Miniature horses are horses. It's right there in the name.

A pony.

Pluto is pony planet.

Little and cute. With big heart (see the photos.) as cutiemark _{iirc, this word}.

Or, like suggested above "ploon", such bodies may be called "plony".
When it's somebody's moon - "ploony".
When you have a plony, it's your ploony.

So, then we have ploonie-Moonie.

Edited October 15, 2020 by kerbiloid

[JoeSchmuckatelli]

28 minutes ago, kerbiloid said:

A pony.

Pluto is pony planet.

Little and cute. With big heart (see the photos.) as cutiemark _{iirc, this word}.

Or, like suggested above "ploon", such bodies may be called "plony".
When it's somebody's moon - "ploony".
When you have a plony, it's your ploony.

So, then we have ploonie-Moonie.

grin

[K^2]

3 hours ago, sevenperforce said:

Second, the point is to identify a binary. "Binary" should be applicable beyond the moon-planet division, and it should be applicable without reference to an external attractor. What about rogue planets? There's no star to deal with, there. A rogue planet is a binary system if the barycentre is ever in free space and it is a satellite system if the barycentre is not ever in free space. You don't need to reference any third body. It doesn't matter what orbit you're in.

Applicable to what? Are you going to apply your binary definition to stars? So what do you call a star orbiting another star, when barycenter is inside the later? Clearly, you don't want to call it a binary.

The planet-moon vs binary planet distinction only makes sense in context of discussing star-planet-moon interactions, because it's actually tells us things about the evolution of a star system. The normal process is for planets to form from protostellar disk and moons to form from protoplanetary disk. That makes the later always gravitationally bound to the planet more than to the star. When we see an exception, something interesting happened. Either the planet migrated into the inner system from where it formed or there was an impact event. If I tell you that Earth has a moon, you say, "So what? So does almost every other planet." But that misses the mark. The Moon is unlike every other body in Sol that we've studied.

Having taxonomy that lets us identify these things in other star systems is crucial. When we start being able to distinguish some of the known exoplanets into multiple bodies, under current definitions, all we're going to say is, "They're moons, probably," because there is no way for us to measure barycenter and most of these really will be just moons, so we'd be just guessing. But we need to inform not just the scientific community but the public when we find something interesting, and finding pairs of objects that are pulled by the parent star more than by each other is interesting. These are discoveries worth knowing about. And that means it's worth distinguishing them in nomenclature. If we find systems like Earth-Moon out there, we should be identifying them as binaries from the moment they are resolved, because it's not just another moon that we expect to be there. It's a signature of a catastrophic event that took place during formation of the system and tells us more about the development of planetary system around that star than any moon ever could.

As for rogue planets, honestly, who cares? While space is probably filled with them, without a proximate star, truth is, we aren't going to find any any time soon. And I would give good odds that we'll never observe a rogue system composed of two similarly-sized objects where calling one the moon of the other would seem odd. Sure, they must statistically exist, but we aren't going to be studying or cataloguing them. So, again, who cares?

I understand wanting to make definition that cuts across all cases everywhere. But that's just stamp collecting, in my opinion. We need practical definitions for practical cases where naming things differently or the same tells us something useful. The definition of the planet was updated to exclude Pluto because calling all sufficiently massive objects planets was becoming useless. We had to change the definition to reflect how planet interacts with the rest of the star system. Just like the tug-of-war definition I'm arguing for, our current official definition of a planet cannot be applied to a rock drifting through interstellar space. It only makes sense for an object orbiting a star. And how massive an object has to be to be considered a planet depends on how close it is to the parent star. Being a planet isn't an intrinsic property of an object. Neither should it be of the planet-moon system. The useful definition of a moon is one that acknowledges interaction with parent star, because it lets us distinguish boring moons from exciting binary planets.

[SOXBLOX]

4 hours ago, sevenperforce said:

...lexemes formed by open compounding, using a modifying dependent along with a noun, strongly imply...

Linguist friend!

4 hours ago, sevenperforce said:

It's easy to make it precise. If the barycentre ever dips beneath the surface of the larger body, it is a satellite system. If it never does, it's a binary system. Applies to stars too.

Yes, but, as much as I like that definition, it has issues, as @K^2 pointed out. The barycentre depends on the distance between the bodies, and that changes. Also, finding the distances between exoplanets and their exocompanions is tricky, right? I'm no expert, but isn't it easier to find the relative masses rather than the barycentre?

[sevenperforce]

Just now, SOXBLOX said:

Linguist friend!

The graduate English electives I took while getting my physics undergrad were some of my favorite classes ever. Linguistics was the best.

Doesn't hold a candle to how much fun law school is, though. 

Just now, SOXBLOX said:

as much as I like that definition, it has issues, as @K^2 pointed out. The barycentre depends on the distance between the bodies, and that changes. Also, finding the distances between exoplanets and their exocompanions is tricky, right? I'm no expert, but isn't it easier to find the relative masses rather than the barycentre?

Well, the distance between the bodies does change, sure. And we won't always be able to determine separation between exoplanet multiples. But that's not really a problem. Things change.

• "Triton used to be a dwarf planet until it was captured by the giant planet Neptune and became a moon."
• "Our moon will continue to move away from us until it is no longer our moon but a planet of its own, forming a binary with us."
• "Pluto and Charon are a dwarf planet binary with such a close mass ratio that they are both tidally locked to each other."
• "We have discovered that there are two different worlds orbiting Gliese 790! We can't yet tell whether they are a binary planet or if one is a moon of the other, but they're large enough to both be potentially habitable."

No problems arise from this usage.

There's another solution, though, if we want to define planetary bodies by their intrinsic properties first, then by their position in a system.

In 2019, Harvard astrophysicists determined that worlds less than 2.7% the mass of Earth would never be able to have liquid water on their surfaces because their gravity was too low to prevent runaway water loss even at the edge of their star's habitable zone, regardless of the size of that habitable zone.

The largest moons in our solar system are less than 2.7% the mass of Earth. The smallest planet (Mercury) is more than 2.7% the mass of Earth. Seems like a good cutoff to me.

[sevenperforce]

Using the Harvard liquid-water definition is a touch arbitrary, but it would make definitions pretty simple. Just five intrinsically-defined classes:

• Star. Any body with a mass greater than 1.5e29 kg.
• Protostar. Any body with a mass greater than 2.5e28 kg but less than 1.5e29 kg.
• Planet. Any body with a mass greater than 1.6e23 kg but less than 2.5e28 kg.
• Protoplanet. Any body with a mass greater than 3.7e19 kg but less than 1.6e23 kg.
• Asteroid. Any body with a mass less than 3.7e19 kg.

A satellite is a body which orbits another body in a higher class than itself. Pairs of orbiting bodies in the same class are called binaries. The satellites of planets and protoplanets are called moons.

Super simple.

[NFUN]

7 hours ago, sevenperforce said:

While I take no offense, I'm also unembarrassed. This is exactly how language works. Not trying to pull rank or anything, but in English common parlance, lexemes formed by open compounding, using a modifying dependent along with a noun, strongly imply that the thing being identified is a subset of the group represented by that noun. Fighter jet, writing desk, compact car, pickup truck, potted plant, garage door. These are all endocentric compounds, where the adjectival dependent modifies and restricts (but does not alter) the meaning of the obligatory head.

Endocentric compound lexemes should be distinguished from ordinary noun phrases, like "the brown desk" or "a small horse" where the adjective denotes a characteristic without defining a subclass.

It is true that we have lexemes in which an open compound (with the adjective+noun structure) is used to denote a new class rather than a subclass. These are exocentric constructions. A red head is not a particular type of head, for example, and a bird house is not a subclass of (the common usage of) houses. But such constructs are the result of evolution and fixation of the lexeme within a dialect, not prescription. If one of our goals in sharing science is to make science accessible to the public, we shouldn't deliberately choose a nomenclature where a modifier+noun combination denotes a new class rather than a subclass. It's inherently confusing.

To borrow one of the examples above, it would be like saying, "Oh, we don't call any land masses islands anymore. We call them dwarf continents. But a dwarf continent is not a type or subclass of continent." That would be ridiculously confusing.

So all of these arguments are that "dwarf planet" is a bad term, which is fair, and not "dwarf planet has 'planet' in the name and therefore they're planets", which is stupid

[sevenperforce]

5 minutes ago, NFUN said:

So all of these arguments are that "dwarf planet" is a bad term, which is fair, and not "dwarf planet has 'planet' in the name and therefore they're planets", which is stupid

No, the argument is that deliberately choosing a compound lexeme like “dwarf planet” to exclude something from being a planet is contrary to how language typically works and is therefore prone to causing confusion.

[NFUN]

3 minutes ago, sevenperforce said:

No, the argument is that deliberately choosing a compound lexeme like “dwarf planet” to exclude something from being a planet is contrary to how language typically works and is therefore prone to causing confusion.

So you're saying that "dwarf planet" is a bad term and not "dwarf planet has 'planet' in the name and therefore they're planets"

[K^2]

4 hours ago, sevenperforce said:

Using the Harvard liquid-water definition is a touch arbitrary, but it would make definitions pretty simple. Just five intrinsically-defined classes:

• Star. Any body with a mass greater than 1.5e29 kg.
• Protostar. Any body with a mass greater than 2.5e28 kg but less than 1.5e29 kg.
• Planet. Any body with a mass greater than 1.6e23 kg but less than 2.5e28 kg.
• Protoplanet. Any body with a mass greater than 3.7e19 kg but less than 1.6e23 kg.
• Asteroid. Any body with a mass less than 3.7e19 kg.

A satellite is a body which orbits another body in a higher class than itself. Pairs of orbiting bodies in the same class are called binaries. The satellites of planets and protoplanets are called moons.

Super simple.

Yeah, but what's the actual utility here? Mercury-sized object out in the Kuiper Belt would be just another snowball. A big snowball, but the thing is, one might actually exist, likely, even, based on some models, and we haven't found it yet, and we aren't really losing any sleep over that. For all intends and purposes it'd be just another KBO. Describing such an object out in the KB as a planet would be silly. In contrast, had the Mercury been as small as the Moon, or even as small as Pluto, it'd still be a significant contribution to inner system.

Besides, we already have a number of categories based on physical characteristics. We have icy objects, terrestrial objects, ice giants, gas giants, and brown dwarves. Many of these can take a number of possible roles, from dwarf planets, to actual planets, to moons. Saying Pluto is an icy dwarf planet says volumes more than "protoplanet" in your definition. While for Titan and Ganymede the defining trait is being icy moons of a gas giant, despite very nearly making the cutoff for a planet in your definition. And the Moon is nowhere near the same kind of object despite being smaller, because it is orbiting the Sun directly. Describing Earth-Moon system as terrestrial binary planet puts it into the correct perspective.

And then we ought to revisit the problem of measuring. We don't have good numbers for a lot of exoplanets out there. We either have lower bounds on mass if we discovered them from spectroscopy methods or estimate from size based on transit method. The situation is going to be way worse with the exomoons. So were we to define things based on mass, whe we will be discovering objects in other star systems, we will neither be able to tell whether they are moons or planets or protoplanets, nor will we actually care, because it doesn't really tell us anything about that particular star system nor, indeed, about conditions on that object. On the other hand, we can tell if the object orbits the star directly or if it's going around a parent object, basically, so long as we can observe it at all. So we'll immediately know if we're dealing with a moon or binary planet, and that distinction tells us something about evolution of that star system, which is what we're really after here.

P.S. I personally have no objections to renaming "dwarf planet" to something else. "Protoplanet" is still a bit misleading, because it kind of implies that it can become a planet - e.g. protoplanetary disk. But I honestly don't care what the term is, so long as we have one. Likewise, I don't particularly care if the binary planets are called double planets instead. I prefer the term binary, but to me personally, the actual choice doesn't make much of a difference.

Edited October 16, 2020 by K^2

[sh1pman]

26 minutes ago, K^2 said:

P.S. I personally have no objections to renaming "dwarf planet" to something else

Maybe just a dwarf? There are giants already, we don’t call Jupiter a “gas giant planet”, just a gas giant. 

But then there are red, brown and white dwarfs which are stars. May cause even more confusion.

Subplanet perhaps?

[NFUN]

22 minutes ago, sh1pman said:

Maybe just a dwarf? There are giants already, we don’t call Jupiter a “gas giant planet”, just a gas giant. 

But then there are red, brown and white dwarfs which are stars. May cause even more confusion.

Subplanet perhaps?

honestly I dig that one. Very clearly indicates that it is not a planet, while still being memorable to laymen of what it represents and doesn't have the issues a term like "protoplanet" does. Plus, it'll make the "I WILL NOT STAND for Pluto being demoted" crowd even more perturbed 

[Bill Phil]

24 minutes ago, sh1pman said:

Maybe just a dwarf? There are giants already, we don’t call Jupiter a “gas giant planet”, just a gas giant. 

But then there are red, brown and white dwarfs which are stars. May cause even more confusion.

Subplanet perhaps?

I've heard "gas giant planet" before.

[kerbiloid]

(Continuing the planetary pony)

We can call a big planet "planet",
a small pony planet (plony) - "plonyt",
and when it's a moon (ploony) - "ploonyt".

Then all three words sound almost same (planet-plonyt-ploonyt),
and their adjectives as well (planetary-plonytary-ploonytary).

So, a trip to the Jupiter _{compromised as a "planet" by Trojans} Saturn is "interplanetary",
to the Pluto - either interplanetary (because of Earth) or "interplonytary" (because of Pluto),
and from Io to Callisto - "interploonytary".

As they sound almost similar, this immediately makes the difference insignificant.
Pronounce it as you wish, everybody will hear what he prefers.

(In MidEast languages they would be even written similarly, TNLP, just a couple of diacritic scratches near the letters may change).

In Tengwar runes, too, btw.

Edited October 16, 2020 by kerbiloid

[JoeSchmuckatelli]

8 hours ago, sevenperforce said:

The graduate English electives I took while getting my physics undergrad were some of my favorite classes ever. Linguistics was the best.

Doesn't hold a candle to how much fun law school is, though. 

...

Law school is indeed awesome.

 

Practicing law, however... Not so much.

[Nuke]

4 hours ago, K^2 said:

Yeah, but what's the actual utility here? Mercury-sized object out in the Kuiper Belt would be just another snowball. A big snowball, but the thing is, one might actually exist, likely, even, based on some models, and we haven't found it yet, and we aren't really losing any sleep over that. For all intends and purposes it'd be just another KBO. Describing such an object out in the KB as a planet would be silly. In contrast, had the Mercury been as small as the Moon, or even as small as Pluto, it'd still be a significant contribution to inner system.

Besides, we already have a number of categories based on physical characteristics. We have icy objects, terrestrial objects, ice giants, gas giants, and brown dwarves. Many of these can take a number of possible roles, from dwarf planets, to actual planets, to moons. Saying Pluto is an icy dwarf planet says volumes more than "protoplanet" in your definition. While for Titan and Ganymede the defining trait is being icy moons of a gas giant, despite very nearly making the cutoff for a planet in your definition. And the Moon is nowhere near the same kind of object despite being smaller, because it is orbiting the Sun directly. Describing Earth-Moon system as terrestrial binary planet puts it into the correct perspective.

And then we ought to revisit the problem of measuring. We don't have good numbers for a lot of exoplanets out there. We either have lower bounds on mass if we discovered them from spectroscopy methods or estimate from size based on transit method. The situation is going to be way worse with the exomoons. So were we to define things based on mass, whe we will be discovering objects in other star systems, we will neither be able to tell whether they are moons or planets or protoplanets, nor will we actually care, because it doesn't really tell us anything about that particular star system nor, indeed, about conditions on that object. On the other hand, we can tell if the object orbits the star directly or if it's going around a parent object, basically, so long as we can observe it at all. So we'll immediately know if we're dealing with a moon or binary planet, and that distinction tells us something about evolution of that star system, which is what we're really after here.

P.S. I personally have no objections to renaming "dwarf planet" to something else. "Protoplanet" is still a bit misleading, because it kind of implies that it can become a planet - e.g. protoplanetary disk. But I honestly don't care what the term is, so long as we have one. Likewise, I don't particularly care if the binary planets are called double planets instead. I prefer the term binary, but to me personally, the actual choice doesn't make much of a difference.

quasi-planets seems a bit less ambiguous. it both indicates that its not quite a planet while acknowledging that it is at least related in form if not in definition. 

[JoeSchmuckatelli]

1 minute ago, Nuke said:

quasi-planets seems a bit less ambiguous. it both indicates that its not quite a planet while acknowledging that it is at least related in form if not in definition. 

Well - now we're quibbling on the term 'quasi' over the term 'dwarf'.  'Dwarf' at least implies that its bearded and nasty with an axe.  'Quasi' suggests it hasn't yet figured out what it wants to be.

[Nuke]

1 minute ago, JoeSchmuckatelli said:

Well - now we're quibbling on the term 'quasi' over the term 'dwarf'.  'Dwarf' at least implies that its bearded and nasty with an axe.  'Quasi' suggests it hasn't yet figured out what it wants to be.

its not sure whether it wants to transition into a planet or get captured by a gas giant and become a moon. 

Edited October 16, 2020 by Nuke

[kerbiloid]

A metaplanet.

They always add "meta-" when it's not clear how to name.