Final answer:
Omega Centauri and M13 are examples of globular star clusters, which are symmetrical systems containing a large number of stars and are among the oldest parts of the Milky Way.
Step-by-step explanation:
Omega Centauri and M13 in Hercules are examples of globular star clusters. These are nearly symmetrical round systems of typically hundreds of thousands of stars or even more.
Omega Centauri, the most massive globular cluster in the Milky Way, is approximately 16,000 light-years away and contains several million stars, including red giants which have expanded and cooled after exhausting their hydrogen fuel. M13, another globular cluster, is found in the constellation Hercules and is also composed of myriad stars densely packed into a spherical shape. Globular clusters like Omega Centauri and M13 are some of the oldest parts of our galaxy, containing very old stars.