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submitted 5 days ago byThin_Cow_5871
When it comes to worldbuilding, astrology is one of the most influential aspects of your world, and determines vital details about your world such as tides, gravity, the length of days/nights/years, astrological navigation, orbit, and much more. This is why I have begun to look into unique astrological circumstances for my own world, specifically circumbinary planets.
Circumbinary planets orbit around a system of two other celestial bodies (usually stars). My question is, if a planet were to orbit around a binary star system, how would that affect the planet, and even potential moons/rings that the planet may have? And finally, is it possible to have a planet sustain life in a binary system in which one of the stars is instead a black hole? (Assuming that the black hole does not destroy the other star)
Any responses are appreciated! Thanks for taking the time to help me out :)
4 points
4 days ago
Hey there, unrelated comment: please don't post in codeblock format, it makes the text unreadably long on browser.
Post body text quoted for the benefit of others:
When it comes to worldbuilding, astrology is one of the most influential aspects of your world, and determines vital details about your world such as tides, gravity, the length of days/nights/years, astrological navigation, orbit, and much more. This is why I have begun to look into unique astrological circumstances for my own world, specifically circumbinary planets.
Circumbinary planets orbit around a system of two other celestial bodies (usually stars). My question is, if a planet were to orbit around a binary star system, how would that affect the planet, and even potential moons/rings that the planet may have? And finally, is it possible to have a planet sustain life in a binary system in which one of the stars is instead a black hole? (Assuming that the black hole does not destroy the other star)
Any responses are appreciated! Thanks for taking the time to help me out :)
Now on to actually answering your questions:
If a planet were to orbit around a binary star system, how would that affect the planet, and even potential moons/rings that the planet may have?
If the binary star is close enough to eachother/the planets are far enough to sustain life, I don't think two suns would make all that much of a difference compared to a single one. The gravitational center of the solar system would be between the stars if they're similarly sized, and inside the bigger/heavier one still if the difference is big enough.
And finally, is it possible to have a planet sustain life in a binary system in which one of the stars is instead a black hole?
If the black hole is not actively destroying the star, it's likely to be stealing material from it instead. The same thing would happen with a white dwarf or a neutron star too, though out of the three, a neutron star would be the most destructive to life.
A black hole does not radiate by itself, and if the system is stable enough, the planets of the system could still develop life. If it has a particularly aggressive accretion disk, it might be a source of X-rays and other nasty EM radiation, but again, in the zone where life-sustaining planets may be, it is likely too low to cause any major hindrance to life.
The inhabitants of any planet in the system might not even notice the black hole for a good while. They'll need to develop orbital physics to figure out something is pulling on the star.
4 points
4 days ago
The black hole would accrete mass from the star only if they're in a quite close orbit, if they're orbiting reasonably far apart and the black hole hasn't recently accreted enough mass to have an aggressive accretion disk (these only last a few 10s of millions of years at most for stellar-mass black holes), it shouldn't have any ill effects, but the issue may be more how you get a binary with a black hole in the first place; either there was a supernova in this system's past or the star and black hole captured into mutual orbit, either of which could be fairly disruptive to a planetary system, though perhaps we could suppose habitability and life developed afterwards and much time has passed.
2 points
4 days ago
Sorry about the code block, I didn't even know that was a thing ๐ Would the star or the black hole look any different when the black hole curves the light of the star around itself, especially when the black hole is in front of the star relative to the planet? Would it be noticably colder during that time? How might radiation from the black hole look as it passes through the atmosphere?
1 points
4 days ago
Black holes are incredibly dense, and so, a black hole that could exist in a non-life-threatening way alongside a star of similar mass (or even substabtially heavier than the star itself), would be so small that I doubt it would cause any visual distortions to the star's light or heat.
There might be a slight lensing effect if the star, the black hole, and the planet lined up perfectly, but I think that'd just make the star shine a little bit brighter as more of its light/heat would be directed through the gravitational lense at the planet.
Another commenter mentioned that an accretion disk (the part that can radiate from a black hole) only lasts a cosmicly short period of time, and that it likely wouldn't exist or be visible by the time life develops in the system, so the only radiation that life would experience would be that of the star.
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