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On astronomy, and sci-fi world building.
12 years ago
General
Hey there, I've a question for anyone who's knowledgeable on matters of astronomy and the like.
I'm tinkering with setting up a solar system for a fictional universe, but I wanted it to have some inkling of realism. This was going to be a binary solar system, one of these stars is a red dwarf. Around this star, orbits the one life-bearing planet in this system. Now, here's where my uncertainties come from.
I know that, red dwarf stars' habitable zones are so close to them that planets within it run the risk of tidal locking (which means that, one face of a satellite always faces what it's orbiting, like our moon). So, I was wondering if the presence of a second star would generate enough pull on the planet to prevent tidal locking.
A secondary curiosity, concerning the same hypothetical star system. Say that second star was a yellow dwarf like our sun. But this star system is very old, and said star has gone through it's life cycle, and become a white dwarf. (The red dwarf need not concern itself with this, since they last the longest of any star)
Would the process of a yellow dwarf swelling to a red giant temporarily, then shedding it's outer layers totally obliterate any planet nearby? Or would it be hypothetically be possible for life to arise on such a planet afterward, since it draws most of it's heat from a different, nearer star?
I'm tinkering with setting up a solar system for a fictional universe, but I wanted it to have some inkling of realism. This was going to be a binary solar system, one of these stars is a red dwarf. Around this star, orbits the one life-bearing planet in this system. Now, here's where my uncertainties come from.
I know that, red dwarf stars' habitable zones are so close to them that planets within it run the risk of tidal locking (which means that, one face of a satellite always faces what it's orbiting, like our moon). So, I was wondering if the presence of a second star would generate enough pull on the planet to prevent tidal locking.
A secondary curiosity, concerning the same hypothetical star system. Say that second star was a yellow dwarf like our sun. But this star system is very old, and said star has gone through it's life cycle, and become a white dwarf. (The red dwarf need not concern itself with this, since they last the longest of any star)
Would the process of a yellow dwarf swelling to a red giant temporarily, then shedding it's outer layers totally obliterate any planet nearby? Or would it be hypothetically be possible for life to arise on such a planet afterward, since it draws most of it's heat from a different, nearer star?
also, said orbits can be pretty complicated, preventing habitable environments. I'm not even sure if there COULD be planets at all.
a yellow dwarf blowing up would hurtle it's stuff all beyond the orbit of Pluto, possibly igniting the nearby red dwarf, too, so that would not leave habitable planets at all. before that happens the yellow dwarf would douse the vicinity with gamma rays and other energies. for example, our earth would be long since dead and molten before the star explodes.
you could either go with a "twilight planet" around a red dwarf, or a planetoid-sized space station in far orbit, I think.
I hope that helps. :)
also remember that the stars would also rotate around each other. or else they would crash into each other and explode.
I think.
of course, you are free to think up circumstances that would make it possible. a lot of awesome sci-fi stories use impossibilities like these. :)
though with the right technology they maybe could survive and stabilize the planetary orbit, who knows.
which then would need a spanking good reason why they didn't look for a less demanding place to live. something a lot of furry fan-writers simply ignore. XD
You need to buy the issue to read the full article, but generally speaking planets with multiple suns come in two categories. Either the stars are close together and the planet orbits the pair of them, or the planet orbits one of them and the other star is fairly distant.
I suspect any planet that orbits a red dwarf of a binary pair and is in its goldilocks zone would need to subscribe to the latter scheme. At which point, the other star would be too distant to prevent lock. Trying to go the other route, with two close stars and the planet orbits the pair, would not allow the planet to be both orbiting stably and close enough to hold liquid water.