A spherical bulge of closely packed stars is called a galactic bulge.

Here's why:

* Spherical: Galactic bulges are generally shaped like a sphere or ellipsoid.

* Closely packed stars: They are densely populated regions with a high concentration of stars.

* Galactic: They are found in the center of most spiral galaxies, including our own Milky Way.

Galactic bulges are distinct from other galactic components like the galactic disk, which contains most of the galaxy's stars and gas, and the galactic halo, which is a sparse outer region.