Astronomers using ESO’s Visible and Infrared Survey Telescope for Astronomy (VISTA) at Paranal Observatory have produced a spectacularly detailed infrared image of the globular cluster NGC 6723.
Globular clusters are systems of very ancient stars, gravitationally bound into a single structure about 100-200 light-years across.
They contain hundreds of thousands or perhaps a million stars. The large mass in the rich stellar center of a cluster pulls the stars inward to form a ball of stars.
Globular clusters are among the oldest known objects in the Universe and are relics of the first epochs of galaxy formation.
It is thought that every galaxy has a population of globular clusters. Our Milky Way Galaxy hosts at least 150 such objects and a few more are likely to exist hidden behind the Galaxy’s thick disk.
“Globular clusters are spherical-shaped groups of stars, tightly bound together by gravity,” ESO astronomers said.
“Their name is derived from the Latin word globulus, meaning small sphere — somewhat misleading given that, as most, contains hundred of thousands to millions of stars.”
NGC 6723 is located approximately 28,000 light-years away from Earth in the constellation of Sagittarius.
Otherwise known as GCl 106, this globular cluster is nearly 13 billion years old.
“Globular clusters were key to pinpointing our own location within the Milky Way in the early 20th century,” the astronomers said.
“American astronomer Harlow Shapley measured the distances to several globular clusters, and noticed that they were arranged in a roughly spherical distribution, but the Sun was not at its center.”
“He correctly inferred that the heart of the Milky Way lays at the center of this distribution of globular clusters, placing the Sun in the suburbs of the Galaxy.”
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