Alternate Planets, Suns, Stars, and Solar Systems Thread

Really neat. I see particular potential for eventual floating colonies in that 7th planet’s atmosphere. Like what some people want to do with Venus, except with more freezing and less “perpetual chance of acids melting your balloon.”
Yes, that would be very possible. Any other ideas?
 
Yes, that would be very possible. Any other ideas?
I wonder about the placement of the asteroid belts, but only because I don’t know the planets’ semimajor axes. Other than that, it’s a system like I don’t think I’ve seen before in fiction. Makes for some interesting ideas about how life on the third world (for example) would interpret the regular changing of the shape of the big blob of light in the sky. But that’s just filagree detail.
 
I wonder about the placement of the asteroid belts, but only because I don’t know the planets’ semimajor axes. Other than that, it’s a system like I don’t think I’ve seen before in fiction. Makes for some interesting ideas about how life on the third world (for example) would interpret the regular changing of the shape of the big blob of light in the sky. But that’s just filagree detail.
Imagine Jupiter as close as Mars, and that is what they would see. The first asteroid belt is about where ours is, the 2nd one is like Uranus or Saturn's distance, and the 3rd one is a bit further than our Kuiper belt in terms of distances.
 
Imagine Jupiter as close as Mars… …the 2nd one is like Uranus or Saturn's distance…
Hmm. I don’t remember enough about orbital resonances to know if that would work. Someone else will know; whether you can have a “sweeper” on the inside of a belt rather than outside. I do think the system might be too compact otherwise. Four super-earths in the space between our Jupiter and our Neptune… I’ll have to crack open Universe Simulator and mock it up to see what happens.
 
Hmm. I don’t remember enough about orbital resonances to know if that would work. Someone else will know; whether you can have a “sweeper” on the inside of a belt rather than outside. I do think the system might be too compact otherwise. Four super-earths in the space between our Jupiter and our Neptune… I’ll have to crack open Universe Simulator and mock it up to see what happens.
Thats just a general idea. Between Jupiter and Neptune is very well possible because we have found systems that cram super earths within the orbit of Mercury.

 
No they are not. The main star is a G type star and the other one below it is an M class star orbiting in a tight binary, think orbiting in 3-5 days or so. I'll give a quick run-down of the planets in the system.

The 1st planet is supposed to be a 1.1-1.6x times the mass of Earth, with a Venus type atmosphere with a different composition.

The 2nd planet is 0.1-0.2 times the mass of Earth. Think Mars but with oceans, a thicker atmosphere and warmer. With a single large moon.

The 3rd planet is an Earth mass world with 2 moons. Quite Earth like.

The 4th planet is a gas giant with different chemicals in its Atmosphere that make it a blue Jupiter type, similar to Jupiter in mass and radius.

The 5th planet is a frozen over planet, with snow and ice everywhere. It's a super Earth type planet.

The 6th planet is similar to Uranus.

The 7th planet is like Neptune but with a more of an Oxygen - Nitrogen Atmosphere. Imagine a gas planet with our Atmosphere.

The 8th planet is very Neptune like with an Earth mass binary companion.

The 9th planet is like Saturn in terms of size though it has different chemicals in its atmosphere that make it a dull red.

The 10th planet isn't even a planet at all, it's a brown dwarf that orbits extremely far out from the system, probably 400-500 AU out.

At the risk of being labelled the snarky nitpicker who ruins a party, you may wish to check your planet order and distance as far as temperature/environment as far as your seventh.

Your 2nd and 3rd are most likely within the normal habitable range and distant enough not to be tidally locked. Given that your seventh planet should not exist given the descriptions of your 5th and 6th; the 5th would most likely beyond the frost line (also known as the snow line or ice line) if indeed it is frozen with snow/ice (assuming H2O based snow and ice) everywhere. If the 6th is like Uranus so basically an ice giant which forms > 20 AU out. Ignoring the fact that oxidizing atmospheres of Earth's composition are the result of photosynthesis and you're dealing with an exponentially larger volume of atmosphere to convert with no solid surface, the seventh planet is then out too far to have the chemicals in our atmosphere be anything but ices. I'd perhaps make your 7th between the 3rd and 4th if you're going for something like a hot Neptune which somehow ended up with an oxidizing atmosphere.
 
At the risk of being labelled the snarky nitpicker who ruins a party, you may wish to check your planet order and distance as far as temperature/environment as far as your seventh.

Your 2nd and 3rd are most likely within the normal habitable range and distant enough not to be tidally locked. Given that your seventh planet should not exist given the descriptions of your 5th and 6th; the 5th would most likely beyond the frost line (also known as the snow line or ice line) if indeed it is frozen with snow/ice (assuming H2O based snow and ice) everywhere. If the 6th is like Uranus so basically an ice giant which forms > 20 AU out. Ignoring the fact that oxidizing atmospheres of Earth's composition are the result of photosynthesis and you're dealing with an exponentially larger volume of atmosphere to convert with no solid surface, the seventh planet is then out too far to have the chemicals in our atmosphere be anything but ices. I'd perhaps make your 7th between the 3rd and 4th if you're going for something like a hot Neptune which somehow ended up with an oxidizing atmosphere.
That makes sense, and yes the 5th planet is covered in H20 based snow and ice. Noted. Anything else? Any ideas for more planets? Since this system is not really completed yet. I'm open to ideas for more planets. Would it be possible for the 7th planet to exist after the 4th planet with a mainly O2 and N2 Atmosphere?
 
That makes sense, and yes the 5th planet is covered in H20 based snow and ice. Noted. Anything else? Any ideas for more planets? Since this system is not really completed yet. I'm open to ideas for more planets. Would it be possible for the 7th planet to exist after the 4th planet with a mainly O2 and N2 Atmosphere?
Depends entirely on the distance from the suns and the irradiance from them. The habitable zone is going to be further out in your system simply because you’re roughly doubling irradiance. You just have to figure out how far in it has to be before you hit the following zones.
 
Depends entirely on the distance from the suns and the irradiance from them. The habitable zone is going to be further out in your system simply because you’re roughly doubling irradiance. You just have to figure out how far in it has to be before you hit the following zones.
My guess is it will be something like 1.5x 1.8x that of ours. The 2nd planet orbits within the inner edge of the habitable zone so we likely have some sort of hot house, wet Earth type planet but with lower gravity. Since its larger than Mars at 0.3 to 0.4x the mass of our Earth or a bit larger, it has a working magnetosphere that keeps the solar radation out.
 
That makes sense, and yes the 5th planet is covered in H20 based snow and ice. Noted. Anything else? Any ideas for more planets? Since this system is not really completed yet. I'm open to ideas for more planets. Would it be possible for the 7th planet to exist after the 4th planet with a mainly O2 and N2 Atmosphere?
The biggest issue I think with Number 7 is the atmosphere and obtaining that atmosphere

Enough mass and you'll have some more internal heating even out to the Snow Line. Problem you end up with is 'How do I get the atmosphere I want?' A hot Neptune will start off as pretty much the same atmosphere as the primordial earth with potentially more hydrogen and helium due to mass. However, you're still going to have Neptunian weather in the atmosphere so we're talking hypersonic winds at various levels and intense pressure at the 'surface' level still, so not the best sort of environment to have any significant amount of primitive life evolving let alone surviving. So you'll be left with a reducing atmosphere as you'll not have enough biomass to induce an 'oxygen catastrophe'.

One idea which I might see working is instead of a hot neptune you have a gas dwarf or mega-earth with an unusually large amount of water (like 20-40%) as it's mass. The atmosphere still resembles primordial earth, but also have enough volatiles and organic chemicals being bombarded or bubbling up from the 'rocky' part of the planet to give you the beginnings of life up on the surface. The stromatalite equivalents would end up like a floating carpet colony of algae, perhaps part of their chemical waste creates a shell like environment that's part of their raft and creates an ecosystem n the water for other microbial life. After a while with this you have the 'oxygen catastrophe' and coupled with outgassing through the dense ocean (through the weird sorts of ice a little ways down to the bottom) the desired atmosphere will end up appearing. Not sure about the weather but I'm guessing pretty calm. Your ideal distance would be far enough from the sun that you don't have a significant amount of the ocean boiling but close enough that it's not frozen on the surface. This world would have a very high albedo I would think as well.

Just some random thoughts.
 
The biggest issue I think with Number 7 is the atmosphere and obtaining that atmosphere

Enough mass and you'll have some more internal heating even out to the Snow Line. Problem you end up with is 'How do I get the atmosphere I want?' A hot Neptune will start off as pretty much the same atmosphere as the primordial earth with potentially more hydrogen and helium due to mass. However, you're still going to have Neptunian weather in the atmosphere so we're talking hypersonic winds at various levels and intense pressure at the 'surface' level still, so not the best sort of environment to have any significant amount of primitive life evolving let alone surviving. So you'll be left with a reducing atmosphere as you'll not have enough biomass to induce an 'oxygen catastrophe'.

One idea which I might see working is instead of a hot neptune you have a gas dwarf or mega-earth with an unusually large amount of water (like 20-40%) as it's mass. The atmosphere still resembles primordial earth, but also have enough volatiles and organic chemicals being bombarded or bubbling up from the 'rocky' part of the planet to give you the beginnings of life up on the surface. The stromatalite equivalents would end up like a floating carpet colony of algae, perhaps part of their chemical waste creates a shell like environment that's part of their raft and creates an ecosystem n the water for other microbial life. After a while with this you have the 'oxygen catastrophe' and coupled with outgassing through the dense ocean (through the weird sorts of ice a little ways down to the bottom) the desired atmosphere will end up appearing. Not sure about the weather but I'm guessing pretty calm. Your ideal distance would be far enough from the sun that you don't have a significant amount of the ocean boiling but close enough that it's not frozen on the surface. This world would have a very high albedo I would think as well.

Just some random thoughts.
Very interesting ideas. I hadn't considered an ecosystem on this planet but that would work. I could also instead of making it it's own planet, it could be a moon of the blue gas giant. The tidal interactions keeping the planet warm even at a Mars like distance. And to replace where it was, there could just be another Neptune style planet.
 
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Very interesting ideas. I hadn't considered an ecosystem on this planet but that would work. I could also instead of making it it's own planet, it could be a moon of the blue gas giant. The tidal interactions keeping the planet warm even at a Mars like distance. And to replace where it was, there could just be another Neptune style planet.
Gas Dwarf or Mega-Earth slightly less 10 Earth Masses but can be similar in size to Neptune or Uranus (up to 3.9 Earth Radii). It would have significant pull on the hot Jupiter (not sure how big you're making this guy) but you'd definitely have heating. Tidal forces would also force volatiles out of the central rocky part much like Io in the Jupiter system so you may even have some odd weather systems / clouds rich in organics and volatile compounds in the atmosphere.
 
Gas Dwarf or Mega-Earth slightly less 10 Earth Masses but can be similar in size to Neptune or Uranus (up to 3.9 Earth Radii). It would have significant pull on the hot Jupiter (not sure how big you're making this guy) but you'd definitely have heating. Tidal forces would also force volatiles out of the central rocky part much like Io in the Jupiter system so you may even have some odd weather systems / clouds rich in organics and volatile compounds in the atmosphere.
We could get weirder here and say that...a 'ring' forms at their barycenter due to trapped debris. Something like this here perhaps. This Gas dwarf would be around 9.7 or 9.6 Earth masses and would orbit around the Jupiter like planet somewhat close but not too close. Think as close as Io is to Jupiter, it would be an extremely interesting system to see.

 
I edited my 'representation' to move that planet to be a moon of the blue gas giant. If someone could run some sort of mockup for this system for stability, I would be quite glad.

 
I made another alternate system based off of our planets. I mostly didn't draw anything on this, I just edited one of those Solar system graphics.

Solar System - Copy - Copy.png
 
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