Gravitational Orbit: How Size Determines Distance & Speed

[Sveral]

Hello,
was just wondering, what determines the gravitational orbit of an object orbitting a planet, for example, Saturn.
Would increasing the size of the object decrease the distance between the object and the planet? Also, what determines the speed at which anything moves throughout it`s orbit-the size of the object or the size of the thing it`s orbitting?
Thanks in advance

 

[mfb]

See the third Kepler law, and in particular the modern version with Newton's law of gravity (replace sun by Saturn and planet by moon).

The size is completely irrelevant, the mass leads to a relation between distance and orbital speed.

 

[Sveral]

See the third Kepler law, and in particular the modern version with Newton's law of gravity (replace sun by Saturn and planet by moon).

The size is completely irrelevant, the mass leads to a relation between distance and orbital speed.

Much appreciated, thank you!