| Astrophysics (Index) | About |
The term radial mixing (radial orbit mixing, radial orbit migration, or radial-orbit instability) refers to the phenomenon of stars changing their distance from the center of the galaxy through their lifetime. Models and observation suggest this occurs, and it is a factor in the interpretation of the star formation history of spiral galaxies, i.e., looking at the characteristics of stars at a particular radius does not fully reflect the previous star formation at that radius. The phenomenon could be relevant to the G-dwarf problem. Long-known epicycles in stellar orbits are a part of the phenomenon.
The term radial mixing is also used regarding the material of protoplanetary disks, considering it to be a factor in planet formation, perhaps incorporating some of the same theory as that for disk galaxies (e.g., Lindblad resonance).