by MarkBour » Sun Jan 23, 2022 10:35 pm
neufer wrote: ↑Sun Jan 23, 2022 6:07 pm
alter-ego wrote: ↑Sun Jan 23, 2022 5:31 pm
https://solarsystem.nasa.gov/resources/12393/telesto-companion-of-tethys/ wrote:
Telesto (24 kilometers, or 15 miles across) shares the orbit of Saturn's moon Tethys (1,071 kilometers, or 665 miles across), leading the larger moon in its path by 60 degrees. Similarly sized Calypso (22 kilometers, or 14 miles across) trails Tethys by the same amount. These positions, called Lagrange points, are dynamically stable. In being co-orbital moons of Tethys, Telesto and Calypso are like the Trojan moons of Jupiter, which occupy Lagrange points and orbit 60 degrees ahead and behind of Jupiter. The Saturnian moon Dione also has companion moons: Helene, which leads Dione in its orbit, and the Cassini-discovered trailing Lagrange moon, Polydeuces.
Note that Tethys & Dione are also in 1:2 orbital resonances with the inner moons: Mimas & Enceladus, respectively.
These two orbital resonances helps to maintain the inner moons' eccentricities which result in:
- 1) Mimas clearing out a wide Cassini Division ring gap and
2) Enceladus spewing out south polar plumes at apoapsis
Interesting. I wonder if the three moons, Telesto, Tethys and Calypso also induce some more complex points of stability where other smaller objects are held? Telesto and Calypso are big enough that they're perturbing Tethys as well. Or, perhaps the three are "cleaning out" the rest of the objects in the orbit.
Cassini would be a top contender for "greatest photographer of the solar system" ... even in black-and-white.
[quote=neufer post_id=320084 time=1642961268 user_id=124483]
[float=right]Animation of Polydeuces/Dione/Helene orbits relative to Saturn
https://upload.wikimedia.org/wikipedia/commons/7/7f/Animation_of_Polydeuces%27s_orbit_relative_to_Saturn_and_Dione.gif[/float]
[quote=alter-ego post_id=320083 time=1642959108 user_id=125299]
[quote="https://solarsystem.nasa.gov/resources/12393/telesto-companion-of-tethys/"]
Telesto (24 kilometers, or 15 miles across) shares the orbit of Saturn's moon Tethys (1,071 kilometers, or 665 miles across), leading the larger moon in its path by 60 degrees. Similarly sized Calypso (22 kilometers, or 14 miles across) trails Tethys by the same amount. These positions, called Lagrange points, are dynamically stable. In being co-orbital moons of Tethys, Telesto and Calypso are like the Trojan moons of Jupiter, which occupy Lagrange points and orbit 60 degrees ahead and behind of Jupiter. The Saturnian moon Dione also has companion moons: Helene, which leads Dione in its orbit, and the Cassini-discovered trailing Lagrange moon, Polydeuces.[/quote][/quote]
Note that Tethys & Dione are also in 1:2 orbital resonances with the inner moons: Mimas & Enceladus, respectively.
These two orbital resonances helps to maintain the inner moons' eccentricities which result in:
[list]1) Mimas clearing out a wide Cassini Division ring gap and
2) Enceladus spewing out south polar plumes at apoapsis[/list]
[/quote]
Interesting. I wonder if the three moons, Telesto, Tethys and Calypso also induce some more complex points of stability where other smaller objects are held? Telesto and Calypso are big enough that they're perturbing Tethys as well. Or, perhaps the three are "cleaning out" the rest of the objects in the orbit.
Cassini would be a top contender for "greatest photographer of the solar system" ... even in black-and-white.