Those stars which, like the Sun, lie in a flattened disk in the Galaxy, and move in nearly circular orbits around its centre. They are Population I stars of all ages up to the age of the disk, but in general are younger than stars in the galactic halo. Disk stars in the solar neighbourhood orbit the Galaxy at similar speeds to the Sun, and therefore have low velocities relative to it. See also Halo Population.
Subjects: Astronomy and Astrophysics.