So I am working on my species which I requested help with a few days ago. They are large salamander like creatures that need large bodies of water to survive and the planet they live on has about 80-90% of its surface covered in deep water. Now from what I have read, a large satellite isn't necessary for this planet and wouldn't be a very likely occurrence. So would a long term ring formation around the planet be stable? I assume a ring around the planet would be just as unlikely, if not more so, but how stable would it be if it could be sustained?

Edit: To explain that this isn't a duplicate of the long term satellite question, I am asking about the possibility of a ring system instead of an orbiting celestial body. The other question doesn't seem to have the answers I am looking for.

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    $\begingroup$ Possible duplicate of Can a tidally-locked planet have a long term natural satellite? $\endgroup$ – rek Dec 18 '18 at 20:19
  • $\begingroup$ Arguably no planet needs a satellite, but why would a water planet be unlikely to have a satellite? We have one, and oceans cover 75% of Earth's surface. $\endgroup$ – Willk Dec 18 '18 at 20:23
  • $\begingroup$ @Willk it's not that it is unlikely on a water planet, but rather the satellite would be unstable because the tidally locked planet would be very close to the parent star. A natural satellite would be very unlikely to keep its orbit. $\endgroup$ – SentiCarter Dec 18 '18 at 20:29
  • $\begingroup$ Rings are millions of "orbiting celestial bodies". $\endgroup$ – rek Dec 18 '18 at 20:30
  • $\begingroup$ @rek that post doesn't go into planetary rings which is what I am looking for. I have read that post to see if it answered my question but I didn't find anything. $\endgroup$ – SentiCarter Dec 18 '18 at 20:31

I'm new here too! I have no idea why you want aquatic amphibians on a water-world tidally locked with its star and surrounded by a dust/ice ring, but let me know how the below sounds!

Rings aren't generally orbitally stable at all; they typically have shepherd moons keeping them from aggregating into a satellite, falling into progressively lower orbits, or being cast away from their parent. It sounds like you've already determined that your planet shouldn't have a moon, so that's out.

But what if the star itself had rings? That usually doesn't happen because of various effects including Poynting–Robertson drag, but a shepherd planet could maintain the rings similar to the way Jupiter maintains the asteroid belt in our solar system.

Why would your system have rings instead of asteroids? Because this is all happening much closer in to the star than the asteroid belts of our system, in the habitual zone of a red dwarf. (This also gives you tidal locking.) Your creatures live under water, so they'd have some protection from the relative violence of their star.

Based on what we see around Saturn and Jupiter, we'd expect your system to have exactly two rings: one just inside the planet's orbit and one just outside it.

A final note though; a tidally locked water world would have some serious "thermal" problems. This could be mitigated by giving it a thick atmosphere and perpetual 100+ kph winds around the equator, but such violent weather would occlude the beautiful and constant meteor shower from the transiting ring-matter.

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  • $\begingroup$ That sounds very interesting, I never thought of that. I will be sure to research the idea. As for the thermal problems, I am still working some things out, but the super storm and thick atmosphere have already been implemented. $\endgroup$ – SentiCarter Dec 18 '18 at 20:37

NASA just released research indicating that planetary rings are not stable formations at all (in geological time). Saturn's rings which were once believed to have formed with the planet billions of years ago are now believed to only be about 100 million years old, and that they will be entirely gone within another 100-300 million years. Basically, the magnetic fields of planets trap particles that are ionized by sunlight resulting in them being pulled out of orbit and raining down onto the planet; so, the existence or non-existence of moons would not actually do much to help maintain a stable ring.

Perhaps a smaller planet might be able to prevent this if it did not have a magnetically active core, but at that smaller mass, and being close enough to the star to have liquid water, you'd probably loose the ring even faster to solar wind.

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