open cluster

noun

, Astronomy.

1. a comparatively young, irregularly shaped group of stars, often numbering up to several hundred, and held together by mutual gravitation; usually found along the central plane of the Milky Way and other galaxies.

open cluster

1. A loose, irregular grouping of stars that originated from a single nebula in the arms of a spiral galaxy. Compared to globular clusters, open clusters generally contain younger and fewer (from a hundred to several thousand) stars and are confined to the disk of the galaxy. Because they are young, open clusters are sometimes still surrounded by the leftover gas and dust from which they formed. Visible from Earth with just a pair of binoculars and containing over 3,000 stars, the Pleiades is the best known open cluster.
2. Also called galactic cluster
3. Compare globular cluster

Example Sentences

Leading the pack is the beautiful open cluster M41, also known as the Little Beehive, which lies only four degrees south of Sirius.

From National Geographic

Thus, switching a finite number of open pipes to closed pipes, or vice versa, does not have any effect on whether an infinite open cluster exists.

From Scientific American

How biased does the coin need to be before enough links are open to guarantee an infinite open cluster?

From Scientific American

That open cluster also goes by the Pleiades or the Seven Sisters.

From Washington Post

This open cluster lies 2,000 light-years from Earth, nestled within the crowded star field of the constellation Sagittarius, the archer.

From National Geographic