Can a star have a ring system?
I often hear about planetary ring systems, and even some moons might have them, but how about stars? Can a star also have rings?
@pela I upvoted your comment, but I wonder if the asteroid belt's distance from the Sun is too large compared with Saturn's distance from its rings. For example, Saturn's rings are closer to Saturn than all of Saturn's major moons, and the asteroid belt is further than 4 planets.
Most or all of the planetary ring systems we know about are within the planet's Roche limit. A star could have a ring of debris within its Roche limit, but it would probably be destroyed fairly quickly by light pressure and stellar wind. (The asteroid belt and the Kuiper belt as *far* outside the Sun's Roche limit.)
They certainly can. A ring is often formed around a celestial body when its gravity rips apart another smaller celestial body. The Sun is really massive, so it could destroy any object that is not dense enough. Just Google about the Roche Limit for more informations (and better explanations).
Now, take a look at our solar system : You have the asteroid belt between Mars and Jupiter, and you also have the Kuiper belt beyond Neptune. Would you consider these being rings ? They sure are not as smooth as Saturn's, but to my mind, they still are rings.
Im pretty sure they are classed as rings - considering they are shaped around the sun like a ring.
I also think they are rings. But I wouldn't consider the Oort cloud being a ring.
Well but at the same time these were surely not created by ripping of some planet because otherwise Mercury would be ripped to pieces
@VojtaKlimes : Mercury would not be destroyed because it has the right density to be above the Sun's Roche Limit. However, I agree with you on the fact that the asteroid belt is not made of broken planets. It is rather rocks that CANNOT agregate together because of Jupiter's gravity pull.
These are quantitatively different to Saturn's rings. The asteroid belt has a spread of inclinations of 20 degrees or so; many are in eccentric orbits. The Kuiper belt is flatter, but still nowhere near as flat as Saturn's rings.
@RobJeffries absolutely. I remember reading somewhere that at some places the rings of Saturn are like 3 meters large at most. Source needed though.
@Nico Yeah, you are probably right, did not thought of that
@VojtaKlimes : Related ;) http://astronomy.stackexchange.com/questions/12723/why-does-saturn-have-both-moons-and-rings?rq=1
Our sun would quickly evaporate and disburse anything inside it's Roche limit. Higher melting point objects tend to be denser and would have Roche limits closer to the sun. Any element would be a gas at it's solar Roche limit and once a gas, it would disburse not coalesce into a ring. https://en.wikipedia.org/wiki/Poynting%E2%80%93Robertson_effect A less massive, colder sun or perhaps a white dwarf might maintain a ring a bit longer.
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pela 7 years ago
Would you be willing to call the asteroid belt the Sun's ring system?