Alternate Planets, Suns, Stars, and Solar Systems Thread

You are still orbiting the sun from a distance of 93 million miles, or one AU. Only this time, the sun isn't a singular G2 yellow dwarf, but a binary of K0 orange dwarves, each one 85% as wide, 78% as massive and only 40% as bright as the sun is in real life. The two orange suns are separated from each other by 0.26 AUs of space.



To make this even more interesting, the suns you're orbiting are themselves orbiting another binary, this time of G0 yellow dwarves (105% as wide, 110% as massive and 126% as bright as our sun) from a distance of 56 billion miles.



What would your sky look like with all the stellar information provided above?
 
You are still orbiting the sun from a distance of 93 million miles, or one AU. Only this time, the sun isn't a singular G2 yellow dwarf, but a binary of K0 orange dwarves, each one 85% as wide, 78% as massive and only 40% as bright as the sun is in real life. The two orange suns are separated from each other by 0.26 AUs of space.



To make this even more interesting, the suns you're orbiting are themselves orbiting another binary, this time of G0 yellow dwarves (105% as wide, 110% as massive and 126% as bright as our sun) from a distance of 56 billion miles.



What would your sky look like with all the stellar information provided above?
Disclaimer, I'm working off Artifexian's solar system-builder guide on Youtube, my knowledge of actual astrophysics is limited. But mates of mine who studied astrophysics tell me that his guide is close enough for quick simulations like this.

Answer: It wouldn't.

To be less cryptic, setting up a close binary pair gives what Artifexian referred to as a Rip-tide Zone. I think the proper name might be the Roche Limit for the pair. But the basics are that there's a certain distance from the barycentre of the pair of stars, inside which a planet will be, at best, flung out of the system, at worst torn apart by their gravity.

Setting up a close pair with the data you gave puts the outer edge of that zone at 1.09 AU from the barycentre, roughly 101 million miles. So you couldn't have a stable planet at only 93 million miles out in order to have a sky.

To riff off the second example, if it were just one distant binary pair and Earth still orbited one of them then the average distance between stars is 602 AU so the further star would average out to appear around 1/(602²), i.e. 1/362,404 or 0.00028%, as bright as our Sun does IIRC. So a normal day/night cycle but with an especially bright star visible in the sky, depending on where the two stars and the planet are relative to each other.
 
THE MIDDLE SOLAR SYSTEM - A MORE PERFECT NEIGHBORHOOD
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The Kemtoid (Asteroid) belt lies between the orbits of Juno and Jupiter, home to millions of small rocks and kemtoids. These were discovered by Egyptian astronomers and historians, and they are named after Egyptian gods. The largest of these in order are Orsis, Horus, Anubis, Thoth, Isis, Nepthis, Sorbek and Nuot. The Kemtoid belt is home to vast collections of resources and precious metals, making it a big target for resource extraction.

Jupiter is the largest of the inner planets, and is a massive gas giant at 142,984 km in diameter. It is made up of white and orange bands streaking across its sky, with many storms and vortexes dominating the planet. The planet possesses a gargantuan moon system, the most well known of which are the six Gallileans, them being Io (a sulfuric volcano world, 3,643 km), Europa (a moon with a massive underground ocean teaming with life, 3,121 km), Ganymede (a large icy moon, 5,262 km), Themis (a massive moon with atmosphere, methane oceans and a small biosphere, 6,270 km), Calisto (an icy cratered moon, 4,820 km) and Moneta (a rocky mineral rich moon, 5,092 km), alongside countless moonlets. Jupiter has Lagrangian companions as well, although they are not as big as Juno’s, known as the Trojan and Greek fields. All of these are 5.221 AU from the sun.

Saturn is the next planet, and it is the second largest in the inner solar system. The planet is well known for its rings made of ice and dust, as well as its pretty big moon system. Saturn is 116,464 km in diameter and is cream colored. Its largest moons are Hyperion (a rocky and icy moon at 3,191 km), Enceladus (a moon with an icy subsurface ocean at 2,724 km), Rhea (basically OTL’s Titan), Phoebe (another rocky and icy moon, 2,384 km) and Tethys (a little more rocky, at 1,862 km). Saturn and its moons are 10.654 AU from the sun.

The next objects beyond Saturn’s orbit are a bit of an oddity. The twin planets of Prometheus and Epimethius are bounded to one another in a binary system. Prometheus is a fiery looking gas giant at around 40,000 km in diameter, while Epimethius is a large rocky and icy body a little less than 20,000 km in diameter, although both bodies have similar masses. They are bound together in a binary system, with Prometheus and Epimethius orbiting an arbitrary point tidally locked about 162,280 km from each of them. The two bodies have a moon system, with the little moons of Menotes and Ankhile orbiting close to the two planets, while the much bigger moon of Atlas orbits further away in an eccentric orbit. Atlas is an interesting place, having a thin atmosphere with an orange-red desert at its surface (Sidenote: Atlas is actually OTL Mars thrown far away from its origin). This group of planets is known as the Japtoid cluster, after the mythical father of the titans the planets are named after, and it is 16.941 AU from the sun.

Uranus comes after the Japtoids, and it is a pretty weird planet. It is tipped over onto its side, with a little ring system. Uranus is about 50,724 km wide, and is a sky blue from space. The planet is an ice giant, a variant of the gas giant that forms far from a star. It has 3 medium sized moons and one large one, the big one being Mimas, which is unusually rocky for its location far out from the sun. The planet is 26.3 AU from the sun.

Neptune is the last of the inner planets from the sun, and it is another ice giant similar to Uranus. Neptune is smaller than Uranus in diameter, at 49,244 km, but it is a little more massive. The planet is a deep blue from space, and is home to a significant moon system, with Polyphemus, Triton and Thalassa dominating it. These moons have irregular orbits, which could mean that they were captured from the Alcythian belt. Indeed, many Alcythian belt objects are similar to the Neptunian moons.
 
Ooh. Cool idea. So Planet Nine (otherwise known as the Fifth Giant) isn’t flung to the far reaches of the solar system TTL, but rather is just pushed outward by inward migrating Jupiter and Saturn… That would make it visible in antiquity (Uranus is technically visible with the naked eye on a very dark night OTL), but Uranus and Neptune wouldn’t be (as you’ve pushed them out). Galileo might even be able to distinguish it and its partner (given its sheer size)…

Also… middle? I’m excited to see outer, then.
 
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You are still orbiting the sun from a distance of 93 million miles, or one AU. Only this time, the sun isn't a singular G2 yellow dwarf, but a binary of K0 orange dwarves, each one 85% as wide, 78% as massive and only 40% as bright as the sun is in real life. The two orange suns are separated from each other by 0.26 AUs of space.
People have said this wouldn't work in reality, and I was inclined to agree with them at first. However, I've just opened up this scenario in Universe Sandbox and let it run for a little over 500 years (not very long, I know, but I fear increasing the time step too much would lead to inaccurate simulation), and it seems to be quite stable (assuming no other planets). This can work for at least a short time.
To make this even more interesting, the suns you're orbiting are themselves orbiting another binary, this time of G0 yellow dwarves (105% as wide, 110% as massive and 126% as bright as our sun) from a distance of 56 billion miles.
This is roughly 602 AU, for reference.
If I've done my math right, each of these distant stars should have magnitude -13.09; roughly 1.4 times the brightness of the full moon.
What would your sky look like with all the stellar information provided above?
At the time of year when you were between the two pairs of stars, it would never really get dark, even at night; the other two stars would each be brighter than the full moon. They would probably eclipse each other frequently - how frequently exactly depends on their distance.
The distant pair of yellow dwarfs would be more or less stationary with respect to the zodiac; by the time they had moved significantly, the zodiac would have changed as well, so we'll treat them as if they have a fixed location in the sky.

The sky would look exactly like on Earth, except for two differences.
Firstly, there would be two suns, so the days would be a bit longer.
Second, one of the constellations would contain two anomalously bright stars that would drown out most of the other starlight when that constellation was visible at night. These two stars would even be visible during the day, although not if they were too close to either sun.
 
People have said this wouldn't work in reality, and I was inclined to agree with them at first. However, I've just opened up this scenario in Universe Sandbox and let it run for a little over 500 years (not very long, I know, but I fear increasing the time step too much would lead to inaccurate simulation), and it seems to be quite stable (assuming no other planets). This can work for at least a short time.


As I've said, I was just plugging in numbers given to me by AbbydonX:


* Twin orange dwarfs: 40% luminosity each
* Approximate habitable zone: 0.80 - 1.52 AU
* Place planets at 0.89 AU (Earth equivalent) and 1.34 AU (Mars equivalent)
* Separate the orange dwarfs by 0.26 AU to make all orbits in the habitable zone stable

* Twin yellow dwarfs: 126% luminosity each
* Approximate habitable zone: 1.43 - 2.70 AU
* Separate the yellow dwarfs by 0.46 AU to make all orbits in the habitable zone stable

* Separation between orange and yellow dwarf binaries is difficult to determine
* 8 AU might allow stable habitable orbits around the orange binary
* 14 AU might allow stable habitable orbits around the yellow binary as well
* Most binaries will be separated by much larger distances though as 14 AU does seem too close

Regardless of the distance between the binaries, the yellow dwarfs will only contribute 1-2% of the light on planets around the orange dwarfs. This might sound low but it would enough to prevent night time if only the yellow stars in the sky. The light level would be somewhere between office lighting or an dark overcast day.
 
As I've said, I was just plugging in numbers given to me by AbbydonX:
Using the equation from here: https://worldbuildingpasta.blogspot...scratch-part-ii-stars.html#binarysystemorbits

Assuming the stars have a negligible orbital eccentricity (Basically, a nearly circular orbit), orbits that have a semi-major axis of more than 0.62075 AU should remain stable long term. (The inner limit is 1.09825AU in the case of the second pair) So in both cases, anything in the habitable zones is stable, with a bit of a buffer zone as well.
 
A quick polish of my previous question. Here's the basic gist of this:

  • No size difference in this rocky planet from Earth
  • 3.1 billion years old, which makes it the oldest body in this solar system. This would suggest that it originally formed in another solar system, only to wander away and get captured by the gravity of a different solar system.
  • It currently orbits a binary of K0 orange dwarves (each one 85% as wide, 78% as massive and only 40% as bright as our sun) from a distance of one astronomical unit. (0.89 AUs would make daylight as bright as Earth, whereas 1.34 would make it as bright as Mars). Each of the orange dwarves is approximately two billion years old.
  • The binary, in turn, orbits another binary, this time of F0 dwarves, each one 120% as wide, 130% as massive and 600% as bright as our sun and one-quarter the age of the orange dwarves, approximately 500 million years old. The distance that the orange-dwarf binary orbits varies depending on the desirability of the given answer, either 2,780,400 miles (the distance in which Neptune orbits the sun) or 56 billion miles (the distance in which Planet Nine orbits the sun.)
  • Orbiting this planet from a distance of 405,000 miles away are two moons, each one approximately 1500 miles wide. Since they are separated by 180 degrees of orbital space, they are essentially given two names upon the initial discovery—Luna Diei (Moon of Day) and Lunan Noctus (Moon of Night).
  • It has a more extreme obliquity, or axial tilt—19.7 to 26.9 degrees, as opposed to our 22.1 to 24.5.


So with all those details listed above, the question is the same as before--what will the 24-hour day-night cycle look like?
 
Just thinking of something here, would it be possible to add some small planets within Mercury's orbit? Like a few Mars mass worlds in an orbital sequence? Can even change the orbit of Mercury to make that fit, does that make sense?

To add onto that idea, how about Ceres being increased in mass to that around twice that of the moon? What has to change for these additions to have formed with the solar system and maintain their stability?
 
Just thinking of something here, would it be possible to add some small planets within Mercury's orbit? Like a few Mars mass worlds in an orbital sequence? Can even change the orbit of Mercury to make that fit, does that make sense?

To add onto that idea, how about Ceres being increased in mass to that around twice that of the moon? What has to change for these additions to have formed with the solar system and maintain their stability?
In response to your first part, it depends on how many you fit and the size of these planets. The gravity of each object depending on where they are placed might throw off the orbits of Mercury or the other objects in the same space within Mercury's orbit.

The second point is impossible without some ASB which I assume you know, Ceres is insanely small in comparison to well most objects. It is a dwarf planet with some cryovolcanic activity, with water vapor emissions on the surface found in 2014. Depending on how large you make Ceres, twice the size of the moon would potentially clear the Asteroid Belt which would make Ceres a Planet. I don't know if this is scientifically possible but the asteroid belt would have to have been condensed and additional mass added somehow to get a body that orbits in that region with twice the moon's size.
 
@BustedMammon

If you ask me personally, I already consider Ceres a planet. As for the extra mass, perhaps one could chalk that up to the idea of added mass in the asteroid belt. I wouldn't wanna get rid of the asteroid belt though, so how about a trojan planet in the orbit of Jupiter about the size of Mars? Would that be possible? Or extra moons around Jupiter that are around the size of the ones currently?

As for the planets inside of Mercury's orbit, let's say we have two planets. The first planet is roughly Lunar mass, and the second one is Pluto mass. How can I fit those there, so it'd be stable?
 
{Sigh...}
I just want the orbital inclination of inner tau Ceti system.
Sadly, as mass of t_C 'f', at chill end of hab-zone, is only constrained by Doppler to Sin(i), could be 3~~5 x mass Earth...
IIRC, there's a big asteroid belt / debris disk at ~35º to 'line of sight', but hints that an outer planet keeps it thus, while the inner planets' orbits are otherwise inclined...
 
@BustedMammon

If you ask me personally, I already consider Ceres a planet. As for the extra mass, perhaps one could chalk that up to the idea of added mass in the asteroid belt. I wouldn't wanna get rid of the asteroid belt though, so how about a trojan planet in the orbit of Jupiter about the size of Mars? Would that be possible? Or extra moons around Jupiter that are around the size of the ones currently?

As for the planets inside of Mercury's orbit, let's say we have two planets. The first planet is roughly Lunar mass, and the second one is Pluto mass. How can I fit those there, so it'd be stable?
Well, it would have to orbit outside the asteroid belt then, as Ceres orbits within the Asteroid Belt and hasn't cleared its orbit. This is why it is considered a dwarf planet, same with Pluto in the Kuiper Belt. It would be possible to have an object of that size within the orbit of Jupiter, I assume it might knock a few moons out of Jupiter's orbit though. This is how you could get get an object that orbits between the Asteroid Belt and Jupiter, or it could get flung into the vast expanse of the Oort Cloud becoming a sort of Rogue Moon.

I don't know much on how stable that would be, there are numerous simulation programs which may be able to help you determine that.
 
@BustedMammon

I believe it would be possible to add extra moons to the gas giants in orbits that wouldn't impact the main moons? Like if you had a Lunar Mass moon around Jupiter,but it's in a highly inclined and eccentric orbit far away from the others.
 
What sorts of colors are plausible for gas giants? I know it's based off gasses, and I know the hues we can see in our own solar system are of course possible, and I remember reading that violet was almost impossible naturally, but what about others? Specifically, greens, whites, and ruby reds.
 
What sorts of colors are plausible for gas giants? I know it's based off gasses, and I know the hues we can see in our own solar system are of course possible, and I remember reading that violet was almost impossible naturally, but what about others? Specifically, greens, whites, and ruby reds.
According to NASA, GJ 504b is believed to be a pink color.
Red, I don't know, but maybe look at Jupiter's red spot, which apparently is thought to have something to do with ammonium hydrosulfide and acetylene. If it's hot enough (i.e. 500+ K), it could have clouds of alkali metals that would give it a red color.
For green, you could try lots of ammonia. Chlorine probably won't work, given how reactive it is.
As for a white gas giant, just have high amounts of water vapor in the clouds. Earth's clouds are white; in a gas giant with plenty of water vapor, there's no reason to think theirs wouldn't be white too.
 
Hello.
I am currently creating a solar system dominated by an intelligent alien species. However I would need your help to know how it would work and its environment.
From what I have imagined so far, this alien race is bipedal and has opposable thumbs. What distinguishes it enormously is that it draws its energy from photosynthesis. Their skin being very close to that of the cactus.
The questions that this premise raises are many:
-What more would it take for these "cactus men" to be realistic?
-How close does their home planet have to be to their sun for them to be able to capture as much light as possible without burning out (assuming that the star is similar to our sun)?
-What would the climate of their home planet be like. For my part I was thinking of a desert planet at the equator and a more temperate climate at the poles with a bush environment between. I was also thinking of a very rich aquatic life in the sea bed.
-What would the fauna and flora of this planet look like where these "cactus men" are the intelligent species? I wanted to be original and imagine it dominated by fungus species as well as corals, but this is not enough to make it a viable ecosystem.
-The "cactus men" in addition to needing light to live would need what else for their survival? Could they rely on other sources of food? Moreover, would they reproduce by pollination ? How do they do it at night ?
-Let's imagine that the "cactus men" succeed in developing social groups and in organizing themselves in society, what would be the common points with our human development on Earth as well as its differences (the use of tools, the mastery of fire, of metallurgy, the construction of cities, nomadic or sedentary)?
I know that I am raising a lot of questions and that some of them may seem rather ridiculous. But I would like to know how to answer them rather than their probability (which I already know is very low).

Thank you in advance for your answers.
 
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