Omega Centauri: A Bright Old Star Cluster

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Explanation: The globular star cluster Omega Centauri contains about 10 million stars, all much older than the Sun, packed into a sphere roughly 150 light-years across.

Also known as NGC 5139, it lies about 15,000 light-years away and is the largest and brightest of roughly 200 known globular clusters that wander the halo of the Milky Way.

While most star clusters contain stars of the same age and chemical composition, Omega Centauri reveals multiple stellar populations with a range of ages and chemical abundances.

In fact, Omega Centauri may be the remnant core of a small galaxy merging with the Milky Way.

With a yellowish hue, the red giant stars of Omega Centauri stand out in this sharp telescopic view.

A twodecadelong exploration of the dense star cluster with the Hubble Space Telescope has revealed evidence for a massive black hole near the center of Omega Centauri.

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