On a ring origin of the equatorial ridge of Iapetus |
On a ring origin of the equatorial ridge of Iapetus |
Guest_AlexBlackwell_* |
Aug 29 2006, 06:18 PM
Post
#1
|
Guests |
Wing Ip just had an interesting Iapetus-related paper published in GRL.
|
|
|
Sep 1 2006, 01:45 PM
Post
#2
|
|
Member Group: Members Posts: 903 Joined: 30-January 05 Member No.: 162 |
I admit a certain favoring of an oblique impact knocking ring forming material into Iapetan orbit. Invoking a similar scenario to that which formed earth's moon (and plausibly Charon too) didn't seem too unlikely.
That a possible Iapetan ring system would be formed from the tidal disruption of a sub-satellite is quite feasible. Early tidal interactions between Iapetus and a possible sub-satellite {hope the IAU doesn't zorch me for invoking apparently unapproved terminology } are interesting to think about. I suspect any such object forming above the synchronous rotation altitude for Iapetus at the time would experience an accelaration force (like our moon today does) and would have been eventually 'lofted' into the void (or at least out of Iapetus' Hill sphere). {Perhaps Hyperion is such an object cast adrift by Titan, also the Dionean, Tethysian, and Enceledosian Trojans, too} Sub-satellites of Iapetus below that altitude would experience a drag force and be subject to disruption inside the Roche limit. Additionally, such close in bodies maybe at further risk of disruption by the 'late accreters' still forming Iapetus. {perhaps the batttered surface of Hyperion records such an epoch from it's possible near Titan 'spawning' grounds} Iapetus having to sweep out such a large volume of space to acrete itself relative to the other Saturnian moons, I think Iapetus took longest to form. {Note, synchronous rotation about Iapetus today is not possible, it's Hill sphere does not extend out to the ~80 day orbit altitude, but in the distant past, prior to Saturnian tide lock, Iapetus would have had a 'Clarke' orbit at a reasonable altitude.} I think the great distance of Iapetus from Titan and Saturn would have provided the possibility of unusally stable and long lasting orbits. I note the difficulty of spacecraft orbiting the earth's moon at low altitudes without station keeping ability and their rapid demise smacking the lunar surface, such as the Apollo subsatellite did. Iapetus would have a 'smooth' and clean gravitational field up close (less any masscon effects) for possible sub-satellites. |
|
|
Lo-Fi Version | Time is now: 26th September 2024 - 02:02 PM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE COPYRIGHT |
OPINIONS AND MODERATION Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators. |
SUPPORT THE FORUM Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |