OK, I’m aware we’ve likely never observed a star wearing rings, but that only says we’ve only seen a small fraction of the observable Universe, let alone the whole thing. And, try as I may, I can’t really come up with a good reason why a star can’t have rings. They don’t have to be pretty to be rings. (I’m guessing the inner, rockier ones would be rather dull.)
I think the problem would be seeing the rings?
That’s not relevant to my question in any way.
Do the asteroid belt and the Kuiper belt not count as the rockier sort of rings you’re asking about? Granted, they’re pretty sparse, but they do they not serve to demonstrate that a star can have rings?
The first problem you’re going to have is that for stable rings to form the particles need to be big enough to shrug off stellar winds and light pressure. But if they are that big, chances are good that they’ll be large enough to begin accumulating mass and forming planetesimals. Being farther out would help but then you run into possible disturbances from other orbiting bodies. My gut feel (and I know this is GQ) is that close solar rings aren’t really possible due to the dynamic environment the particles could find themselves in.
I guess a cool M class star, or brown dwarf might be quiet enough to work. But rings may not be long lived compared to a star’s life.
AFAIK, no ring system is stable over a long time.
its thought that Saturn’s rings might only be a couple 100 million years old, they they may coalesce into new moons over time.
cite:
similarly all stars which form planets are thought to start as protoplanetary discs. That looks a lot like rings to me.
Right. OK, I didn’t know rings were that unstable, so I guess that answers my question.
It’s possible that Saturn’s rings date to it’s formation. In theory, ring systems can be stable for very long periods of time.
Here is an image of a ring around a star. Our own star is surrounded by a kind of ring the Zodiacal cloud. (While it’s called a cloud, I think I’m right in saying there is more dust in the plane of the ecliptic). So it is possible for a star to be surrounded by a (very tenuous) ring system. I don’t think it would be possible for a star to have a spectacular ring system like Saturn.
I think stars often have rings. Especially, at some point in their evolution, they would have lots of material in rings. This is the stuff planets condense out of. I’d guess if we could see star rings clearly we would see lots of examples, even if the pretty phase is brief (there being many stars to choose from).
Why wouldn’t a solar system and/or asteroid belt be considered the rings of a sun?
Because a ring implies at least some sort of integrity to the shape. N chucks of rock whipping round a star in discreet distances doesn’t really work. A “zodiacal” cloud is maybe the best analog but even then I’m not sure how visible it would be to an observer outside of the system in question.
And if we’re going to define rings around a star as being similar to rings around a planet like Saturn, then shouldn’t the rings form for the same reason—i.e., they’re too close to the object to form into a proper single satellite (due to tidal forces). The ringed planets don’t have moons orbiting nearer than the innermost ring. So I don’t believe that the asteroid/Kuiper belts qualify on those grounds. They’d have to be within the orbit of Mercury.
Would an Accretion Disk around a neutron star or black hole count? Certainly sounds like it’d be spectacular to see (from a distance…)
Correct; that’s what makes it zodiacal.
Wow. Harsh reply!