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As a body of a suitable size and mass moves within the Roche limit of a planet, it will disintegrate. This will form a debris field that will eventually form a planetary ring. Is there a name given to this debris field before it forms a ring? Something like a Roche train or Roche field seem appropriate but I can't find any reference to such

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  • $\begingroup$ I've heard some use the terms debris field or accretion disk, since scattered debris may yet reform into a moon or be absorbed by the planet. I'm unsure if any 'official' terms exist. $\endgroup$ – user10106 Mar 6 '18 at 10:08
  • $\begingroup$ Thanks for your reply kozaky! In the absence of any 'official' name I would like to propose a 'Roche hose' $\endgroup$ – Dan Mar 6 '18 at 10:54
  • $\begingroup$ This isn't really the place for proposing new names or terms (this will apply to your Mars moon question too). $\endgroup$ – user10106 Mar 12 '18 at 11:21
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I don't think such an intermediate state exists for very long. Once you shred the moon, it's shredded and the particles orbit on locally Keplerian orbits.
This would look like Saturns rings, which are also well inside the planet's Roche limit.

The intermediate state you propose to name would have to form either
a) a steaty state of in some dynamic variable or
b) have a sufficiently long lifetime (which would be your job to prove)
in order to earn its own name.


Edit: As OP has asked for material on ring spreading, I can point to A. Crida's work who had a bit of a controversial idea about the origin of the gas giant moons. However his calculations involve also classical calculations of collisional disc spreading.

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  • $\begingroup$ Yes I agree the question is how long a debris lasts until it forms a ring. But then again that process could take a substantially long period of time $\endgroup$ – Dan Mar 6 '18 at 11:32
  • $\begingroup$ @Dan [citation needed] Why would you think so? I can imagine that the radial spreading of material takes some time. In that case one would simply distinguish between a narrow and a wide ring, or something along those lines. $\endgroup$ – AtmosphericPrisonEscape Mar 6 '18 at 11:39
  • $\begingroup$ However I would point out that yourself have said that an intermediate stage must exist. The step from disintegration to planetary ring cannot be instantaneous. A relatively small body, say of 50kms in diameter would take a substantial amount of time to disperse into a ring surely? Plus all the fragments would stay in the same orbit only gradually dispersing? $\endgroup$ – Dan Mar 6 '18 at 11:46
  • $\begingroup$ @Dan Well, "A relatively small body, say of 50kms in diameter would take a substantial amount of time to disperse into a ring surely?" is where you need a source on. Also substantial compared to what? You can't let human intuition guide you in that. With the second statement I agree, as there are works on ring spreading. If you're interested I can update my answer with that. $\endgroup$ – AtmosphericPrisonEscape Mar 6 '18 at 11:57

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