This image from the NASA/ESA Hubble Space Telescope reveals a glowing, ancient globular cluster called NGC 3201, a gathering of hundreds of thousands of stars bound together by gravity. NGC 3201 was discovered in 1826 by Scottish astronomer James Dunlop, who described it as a “quite large and quite bright” object that becomes “rather irregular” toward its center.
Globular clusters are found around all large galaxies, but their origin and role in galaxy formation remain surprisingly unclear. Astronomers recently discovered a black hole lurking at the heart of NGC 3201; Its position was revealed by the strange movements of a star hurtling rapidly around a massive, invisible counterpart. This bright group of stars also has some strange properties that make it unique among the more than 150 globular clusters that belong to the Milky Way. NGC 3201 has an extremely fast speed relative to the Sun and its orbit is retrograde, meaning that it is moving rapidly in the opposite direction to the galactic center, which it orbits.
The unusual behavior of this cluster suggests that it may have extragalactic origins, but at some point it was captured by the gravity of the Milky Way. However, the chemical composition of this intriguing cluster tells a different story: the stars within NGC 3201 are chemically very similar to those in other galactic globular clusters, implying that they formed at a similar place and time to their neighbors. .
Whether this mysterious cluster has been adopted by our galaxy or, for some reason, has evolved very differently from the family of clusters it grew up with, it is certainly an unusual astronomical beauty.
Image credit: ESA/Hubble and NASA
Explanation from: https://www.spacetelescope.org/images/potw1804a/
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