Chrysalis

A family-member directs me to Saturn's Rings. Probably formed from the breakup of a Saturnine moon: maybe 200-100 Mya, during our late Triassic or Jurassic. The question is, why did this moon break up so [geologically] recently, and not during the Grand Tack it shared with Jupiter.

For some years we've seen the inner-from-Titan moons as young and in fact dynamically impossible.

h/t to WSJ since I have no access to Maryame El Moutamid's "editorial" DOI: 10.1126/science.abq318. To the editors, I recommend not claiming Saturn (9.5 AU semimajor) and Neptune (30 AU) to be "nearby" - to us, nor to each other.

Jack Wisdom et al. claim that resonances between Saturn and, er, Neptune account for the jostulation of Saturn's moons at the time, running "Chrysalis" into the subMimas orbit so dooming it to fragmentation.

It is however true that these two outer icy planets are close to resonance, 5:28 at a 1.9° mismatch per 5 Saturnine years. This compares well with Earth:Venus 8:13 claimed 1.5° per 13 Earth years.

MIT (and not WSJ) argue, assert anyway, how a Iapetus-class moon could disrupt that resonance. Elliptical interference between Titan and Iapetus - they claim. Possibly driving Iapetus to the distance it's now at. Possibly devouring more ice moons.

I'd look more to Uranus, which is almost Neptune's mass and flies almost exactly between Saturn and Neptune at 20 AU.