Let's create an alien biosphere!

[Schiaparelliorbust]

The direction of rotation shouldn't matter much, so let's use prograde because that's more realistic. As for day length, I see no reason to depart from the day length used in Biblaridion's series (which I believe is twenty hours).

Okay then. Artifexian also has a whole video on retrograde climate if you're interested, though as you said it doesn't seem to matter much. Should the orbital period of the moon be shorter and keep it close to the planet or a bit farther out with a longer period? I say the former for the larger tides.

[MathAndCode]

Okay then. Artifexian also has a whole video on retrograde climate if you're interested, though as you said it doesn't seem to matter much. Should the orbital period of the moon be shorter and keep it close to the planet or a bit farther out with a longer period? I say the former for the larger tides.

Yes, I agree. We should have large tides. Speaking of which, since we're increasing the mass of the planet, I think that we should increase the mass of the moon proportionally.

[Schiaparelliorbust]

Yes, I agree. We should have large tides. Speaking of which, since we're increasing the mass of the planet, I think that we should increase the mass of the moon proportionally.

Any specific reason why you want that? Is it because they might have formed from the same materials? Also, I say that the length of the year should be about 50% longer than Earth's.

[MathAndCode]

Any specific reason why you want that? Is it because they might have formed from the same materials?

That's one of my reasons; my other main reason is because the planet's increased gravity would decrease the tides if the Moon's gravitational pull on the water were the same. However, if the planet has constant density, then surface gravity is the cube root of mass, and smaller moons relative to the planet are more realistic anyway, so I guess that we don't need to increase the Moon's mass as much.

Also, I say that the length of the year should be about 50% longer than Earth's.

I don't think that we should worry about the length of a year for its own sake. Instead, we should focus on making sure that the planet is in the habitable zone. (Or is that what you meant?)

[Schiaparelliorbust]

That's one of my reasons; my other main reason is because the planet's increased gravity would decrease the tides if the Moon's gravitational pull on the water were the same. However, if the planet has constant density, then surface gravity is the cube root of mass, and smaller moons relative to the planet are more realistic anyway, so I guess that we don't need to increase the Moon's mass as much.

We could place it even closer for a stronger gravitational pull. This would also be realistic because our Moon has been moving away over time, so it was much closer to begin with. We could assume the same thing here.

I don't think that we should worry about the length of a year for its own sake. Instead, we should focus on making sure that the planet is in the habitable zone. (Or is that what you meant?)

Yeah, we should focus more on the habitable zone. How much further away would it be in this stellar system because it's a binary one?

[MathAndCode]

We could place it even closer for a stronger gravitational pull. This would also be realistic because our Moon has been moving away over time, so it was much closer to begin with. We could assume the same thing here.

Yes, that sounds fine as long as we remember about the Roche limit.

Yeah, we should focus more on the habitable zone. How much further away would it be in this stellar system because it's a binary one?

The total luminosity would be 1.512 times that of Earth's Sun, so the habitable zone would be about 1.23 times farther out (if everything else is the same).

[Schiaparelliorbust]

Yes, that sounds fine as long as we remember about the Roche limit.

The Roche limit requires the density of the satellite. I doubt we would place it that close but I still want to be careful. We should also calculate density of the planet, and while it is not necessary for the Roche limit, it is still worth knowing.

The total luminosity would be 1.512 times that of Earth's Sun, so the habitable zone would be about 1.23 times farther out (if everything else is the same).

We should place the planet slightly closer than that though because the suns will sometimes eclipse each other and because the lighter sun is a little colder. We will probably have two sets of "seasons", one because of the tilt and another because of the suns eclipsing each other. We should figure out how fast the suns orbit each other relative to the planet orbiting them.

[MathAndCode]

We should place the planet slightly closer than that though because the suns will sometimes eclipse each other and because the lighter sun is a little colder. We will probably have two sets of "seasons", one because of the tilt and another because of the suns eclipsing each other. We should figure out how fast the suns orbit each other relative to the planet orbiting them.

Here is the relevant Artifexian video. (The video has an error about the eccentricities; the two stars must have the same eccentricity as each other.) In order for the habitable zone to allow gravitational orbits, the stars need to orbit each other fairly closely, so the length of their orbit will be short enough that we shouldn't worry about it causing seasons. Also, I just had an idea: If instead of the stars orbiting close together, they orbit farther apart, and the planet orbits in a Lagrange point, then we won't have to worry about the stars eclipsing each other. The day would be somewhat longer, but there would still be nighttime.

[Schiaparelliorbust]

Here is the relevant Artifexian video. (The video has an error about the eccentricities; the two stars must have the same eccentricity as each other.) In order for the habitable zone to allow gravitational orbits, the stars need to orbit each other fairly closely, so the length of their orbit will be short enough that we shouldn't worry about it causing seasons.

Then we should figure out they distances for the forbidden zone, frost line, and habitable zone.

Also, I just had an idea: If instead of the stars orbiting close together, they orbit farther apart, and the planet orbits in a Lagrange point, then we won't have to worry about the stars eclipsing each other. The day would be somewhat longer, but there would still be nighttime.

Yes. We could place it in L4 or L5. Do they form perfect regular triangles with the suns? If so, I might be able to calculate the portion of the day that is in nighttime, but it could be hard.
Edit: I don't know why I said it would be hard, I think it's exactly 1/3 of the day which is nighttime.

[MathAndCode]

Then we should figure out they distances for the forbidden zone, frost line, and habitable zone.

The habitable zone is between 1.168 and 1.685 Astronomical Units, the frost line is at 5.964 Astronomical Units, and planets must be within 72 Astronomical Units of the two stars' barycenter in order to be gravitationally bound. I'm not going to bother calculating the Roche limit because the inner limit of orbital stability will make it obsolete. In order for someone to be able to calculate the inner limit of orbital stability, you will need to decide on certain aspects of the two stars' orbit. There are a variety of orbital characteristics, but defining the eccentricity and either the orbital period or the semi-major axis will be sufficient.

Yes. We could place it in L4 or L5. Do they form perfect regular triangles with the suns? If so, I might be able to calculate the portion of the day that is in nighttime, but it could be hard.
Edit: I don't know why I said it would be hard, I think it's exactly 1/3 of the day which is nighttime.

Yes, they would continue to form equilateral triangles, so day will be twice as long as night instead of being the same length. If we do this, it will result in several changes to the Solar System. First of all, I don't know whether or how high eccentricity would affect Lagrange points' position and/or stability, so let's assume that the eccentricity is relatively low. If the equilateral triangle holds completely even for noncircular orbits, then the stars' orbital eccentricity must be at most 0.181 in order for the planet to stay in the habitable zone. (Also, in this scenario, seasonal variations due to orbital eccentricity will be synchronized with seasonal variations due to axial tilt.) The L₄ and L₅ Lagrangian points are the only two places anywhere close to a habitable distance from the stars where planets can be placed. (There are three other Lagrangian points are not stable, so planets could not realistically be there.) Each of the stable Lagrangian points can hold at most one planet, but each planet can have moons (and, in fact, should have at least one large moon if we want life to evolve there). Also, we can have planets orbiting only one star or orbiting the two stars from much farther out. Most of the limits will depend on factors that haven't been specified yet, but P-type planets will be able to orbit the primary star at radii approximately between 0.1 and 0.4 Astronomical Units, P-type planets will be able to orbit the secondary star at radii approximately between 0.08 and 0.4 Astronomical Units, and S-type planets will be able to orbit the star at radii between about 4.5 and 72 Astronomical Units. Also, the frost line will be at 5.96 Astronomical Units.

[Schiaparelliorbust]

The habitable zone is between 1.168 and 1.685 Astronomical Units, the frost line is at 5.964 Astronomical Units, and planets must be within 72 Astronomical Units of the two stars' barycenter in order to be gravitationally bound. I'm not going to bother calculating the Roche limit because the inner limit of orbital stability will make it obsolete. In order for someone to be able to calculate the inner limit of orbital stability, you will need to decide on certain aspects of the two stars' orbit. There are a variety of orbital characteristics, but defining the eccentricity and either the orbital period or the semi-major axis will be sufficient.

Thank you for calculating them! The video says that we should make the average distance between the stars between 0.15 and 6 AU, though it says we should try and stick to the extreme low end of that range if we want it to be habitable. But if we want our planet in G4 or G5, then it will be at the same distance from both suns as they are from each other, so we either have to put the planet at L4 or L5 and put the suns a bit far away so the planet will be in the habitable zone but that will make the intrasolar (as apposed to interstellar) distance not on the far low end, or do the exact opposite.

Yes, they would continue to form equilateral triangles, so day will be twice as long as night instead of being the same length. If we do this, it will result in several changes to the Solar System. First of all, I don't know whether or how high eccentricity would affect Lagrange points' position and/or stability, so let's assume that the eccentricity is relatively low. If the equilateral triangle holds completely even for noncircular orbits, then the stars' orbital eccentricity must be at most 0.181 in order for the planet to stay in the habitable zone. (Also, in this scenario, seasonal variations due to orbital eccentricity will be synchronized with seasonal variations due to axial tilt.) The L₄ and L₅ Lagrangian points are the only two places anywhere close to a habitable distance from the stars where planets can be placed. (There are three other Lagrangian points are not stable, so planets could not realistically be there.) Each of the stable Lagrangian points can hold at most one planet, but each planet can have moons (and, in fact, should have at least one large moon if we want life to evolve there). Also, we can have planets orbiting only one star or orbiting the two stars from much farther out. Most of the limits will depend on factors that haven't been specified yet, but P-type planets will be able to orbit the primary star at radii approximately between 0.1 and 0.4 Astronomical Units, P-type planets will be able to orbit the secondary star at radii approximately between 0.08 and 0.4 Astronomical Units, and S-type planets will be able to orbit the star at radii between about 4.5 and 72 Astronomical Units. Also, the frost line will be at 5.96 Astronomical Units.

I think you got P and S type stars mixed up. Are we even going to do anything with other planets? If we're going to place our planet anywhere other than the Lagrange points, I think we should make them P type so as to heed Artifexian's warning about placing the suns close together.

To anyone else looking at this thread:
I invite you to come contribute. I think having only two people primarily involved here can unfortunately lead to a shortage of ideas and opinions, which is what drives something like this forward. Having even one other person would be really nice and would definitely make things more interesting.

[HelicopterCat3]

So this planet is bigger than earth right? What about the poles? Does the climate differ by longitude like it does on Earth? Are there any cold regions?

I guess what I'm basically asking is if there are any biomes on this planet

[MathAndCode]

The video says that we should make the average distance between the stars between 0.15 and 6 AU, though it says we should try and stick to the extreme low end of that range if we want it to be habitable. But if we want our planet in G4 or G5, then it will be at the same distance from both suns as they are from each other, so we either have to put the planet at L4 or L5 and put the suns a bit far away so the planet will be in the habitable zone but that will make the intrasolar (as apposed to interstellar) distance not on the far low end, or do the exact opposite.

That distance range and the advice to stick to the low end only apply to P-type planets, which do not include planets in the stars' Lagrange points. For L₄ and L₅, the distance between the two stars will be the same as the distance from each star to the planet, at least if the stars orbit each other with an eccentricity of zero.

I think you got P and S type stars mixed up.

Thank you for pointing that out; otherwise, I would probably make the same mistake again in the future.

Are we even going to do anything with other planets? If we're going to place our planet anywhere other than the Lagrange points, I think we should make them P type so as to heed Artifexian's warning about placing the suns close together.

We don't have to place other planets there, but it is an option. Depending on how far we go into the development on life on the habitable planets, we might want to consider it so that when life that arises on the habitable planets becomes intelligent and develops spaceflight, it will have more mining opportunities.

[Schiaparelliorbust]

So this planet is bigger than earth right? What about the poles? Does the climate differ by longitude like it does on Earth? Are there any cold regions?

I guess what I'm basically asking is if there are any biomes on this planet

We're still figuring out where the suns and planets are. It has 20% more surface gravity than Earth.

That distance range and the advice to stick to the low end only apply to P-type planets, which do not include planets in the stars' Lagrange points. For L₄ and L₅, the distance between the two stars will be the same as the distance from each star to the planet, at least if the stars orbit each other with an eccentricity of zero.

So what distance do you suggest?

I think you got P and S type stars mixed up.

Thank you for pointing that out; otherwise, I would probably make the same mistake again in the future.

Sorry, I meant planets.

Are we even going to do anything with other planets? If we're going to place our planet anywhere other than the Lagrange points, I think we should make them P type so as to heed Artifexian's warning about placing the suns close together.

We don't have to place other planets there, but it is an option. Depending on how far we go into the development on life on the habitable planets, we might want to consider it so that when life that arises on the habitable planets becomes intelligent and develops spaceflight, it will have more mining opportunities.

I prefer having them, though we can just create them from scratch if a civilization reaches that stage.

[MathAndCode]

So what distance do you suggest?

Anything in the habitable zone should be okay, although erring on the closer side might be better.

[Schiaparelliorbust]

Anything in the habitable zone should be okay, although erring on the closer side might be better.

The habitable zone is between 1.168 and 1.685 Astronomical Units.

Do these figures still hold here?

So this planet is bigger than earth right? What about the poles? Does the climate differ by longitude like it does on Earth? Are there any cold regions?

I guess what I'm basically asking is if there are any biomes on this planet

I forgot to include something, the one supercontinent will stretch from one pole to the equator for climate diversity. There is no reason climate shouldn't differ by longitude either, unless it spins like Uranus.

[MathAndCode]

Do these figures still hold here?

Yes.

[Schiaparelliorbust]

Yes.

Could you please calculate where you want the planet to be in the habitable zone then? I don't know nearly enough to do it myself. Is 3°C hotter on average good? Or is that too simple?

[MathAndCode]

Could you please calculate where you want the planet to be in the habitable zone then? I don't know nearly enough to do it myself. Is 3°C hotter on average good? Or is that too simple?

Let's put the planet 1.2 Astronomical Units away from each star; that will be analogous to Biblaridion's planet's distance from its star (adjusted for the fact that the habitable zone is in a different position).

[Schiaparelliorbust]

Let's put the planet 1.2 Astronomical Units away from each star; that will be analogous to Biblaridion's planet's distance from its star (adjusted for the fact that the habitable zone is in a different position).

Ok, that sounds good to me. Are we also done with the suns' masses or not? I would like to get started with the actual life on this planet soon.

[MathAndCode]

Ok, that sounds good to me. Are we also done with the suns' masses or not? I would like to get started with the actual life on this planet soon.

I thought that we had settled on 1.0 and 0.8 solar masses.

[Schiaparelliorbust]

I thought that we had settled on 1.0 and 0.8 solar masses.

I'm totally fine with that. So are we done with the solar system and other celestial body-related stuff?

[MathAndCode]

I'm totally fine with that. So are we done with the solar system and other celestial body-related stuff?

Since we have two habitable planets now, should we set characteristics such as mass and atmospheric composition for each individually, or should we just let them be the same? We can assume that the planets will each spin prograde, so seeing the suns in opposite orders will introduce slight variation, but it won't be very much.

[Schiaparelliorbust]

Since we have two habitable planets now, should we set characteristics such as mass and atmospheric composition for each individually, or should we just let them be the same? We can assume that the planets will each spin prograde, so seeing the suns in opposite orders will introduce slight variation, but it won't be very much.

Wait since when did we have two planets? I don't see any post where you explicitly mentioned having two of them.

[MathAndCode]

Wait since when did we have two planets? I don't see any post where you explicitly mentioned having two of them.

I mentioned that we could have one habitable planet at each stable Lagrange point, but now that I look back at the posts, I see that we didn't actually agree on it. Do you think that we should have two stable Lagrange points?