Reference Terms
from Wikipedia, the free encyclopedia
Open cluster
An open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud, and are still loosely gravitationally bound to each other. In contrast, globular clusters are very tightly bound by gravity. Open clusters are found only in spiral and irregular galaxies, in which active star formation is occurring. They are usually less than a few hundred million years old: they become disrupted by close encounters with other clusters and clouds of gas as they orbit the galactic centre, as well as losing cluster members through internal close encounters.
Young open clusters may still be contained within the molecular cloud from which they formed, illuminating it to create an H II region. Over time, radiation pressure from the cluster will disperse the molecular cloud. Typically, about 10% of the mass of a gas cloud will coalesce into stars before radiation pressure drives the rest away.
Open clusters are very important objects in the study of stellar evolution. Because the stars are all of very similar age and chemical composition, the effects of other more subtle variables on the properties of stars are much more easily studied than they are for isolated stars. The most prominent open clusters such as the Pleiades have been known and recognised as groups of stars since antiquity.
Related Stories
1
2
Space & Time News
November 16, 2025
Nov. 16, 2025 Researchers combined deep learning with high-resolution physics to create the first Milky Way model that tracks over 100 billion stars individually. Their AI learned how gas behaves after supernovae, removing one of the biggest computational ...
Nov. 16, 2025 Dark matter may be invisible, but scientists are getting closer to understanding whether it follows the same rules as everything we can see. By comparing how galaxies move through cosmic gravity wells to the depth of those wells, researchers found ...
Nov. 13, 2025 Researchers engineered “gyromorphs,” a new type of metamaterial that combines liquid-like randomness with large-scale structural patterns to block light from every direction. This innovation solves longstanding limitations in quasicrystal-based ...
Nov. 13, 2025 Arctic sea ice is disappearing fast, and scientists have turned to an unexpected cosmic clue—space dust—to uncover how ice has changed over tens of thousands of years. By tracking helium-3–bearing dust trapped (or blocked) by ancient ice, ...
Nov. 10, 2025 New research from UBC Okanagan mathematically demonstrates that the universe cannot be simulated. Using Gödel’s incompleteness theorem, scientists found that reality requires “non-algorithmic understanding,” something no computation can ...
Nov. 2, 2025 A team of astronomers used the James Webb Space Telescope to create the first 3D atmospheric map of an exoplanet. The fiery WASP-18b, a massive “ultra-hot Jupiter,” revealed striking temperature contrasts, including regions so hot they destroy ...
Oct. 30, 2025 Scientists have developed a groundbreaking tool called Effort.jl that lets them simulate the structure of the universe using just a laptop. The team created a system that dramatically speeds up how researchers study cosmic data, turning what once ...
Oct. 29, 2025 Tohoku University researchers have found a way to make quantum sensors more sensitive by connecting superconducting qubits in optimized network patterns. These networks amplify faint signals possibly left by dark matter. The approach outperformed ...
Oct. 27, 2025 Two Sydney PhD students have pulled off a remarkable space science feat from Earth—using AI-driven software to correct image blurring in NASA’s James Webb Space Telescope. Their innovation, called AMIGO, fixed distortions in the telescope’s ...
Oct. 25, 2025 A UCLA-led team has achieved the sharpest-ever view of a distant star’s disk using a groundbreaking photonic lantern device on a single telescope—no multi-telescope array required. This technology splits incoming starlight into multiple ...
Oct. 25, 2025 Researchers propose that hydrogen gas from the early Universe emitted detectable radio waves influenced by dark matter. Studying these signals, especially from the Moon’s radio-quiet environment, could reveal how dark matter clumped together ...
Oct. 15, 2025 3I/ATLAS, a mysterious interstellar object racing toward the Sun, is baffling scientists with its speed and origin. Some researchers suggest it could even be alien-made, drawing comparisons to probes ...
Latest Headlines
updated 12:56 pm ET
Nov. 16, 2025 LHAASO has uncovered that micro-quasars, black holes feeding on companion stars, are powerful PeV particle accelerators. Their jets produce ultra-high-energy gamma rays and protons that exceed ...
Nov. 16, 2025 Researchers at KRISS observed water’s rapid freeze–melt cycles under ultrahigh pressure and discovered Ice XXI, the first new ice phase found in decades. Using advanced high-pressure tech and ...
Nov. 14, 2025 A massive, well-preserved impact crater has been uncovered in Guangdong, revealing the signature of a powerful meteorite strike during the Holocene. ...
Nov. 14, 2025 Scientists have finally confirmed a powerful coronal mass ejection from another star, using LOFAR radio data paired with XMM-Newton’s X-ray insights. The eruption blasted into space at ...
Nov. 13, 2025 A newly detected super-Earth just 20 light-years away is giving scientists one of the most promising chances yet to search for life beyond our solar system. The discovery of the exoplanet orbiting in ...
Nov. 13, 2025 Simulations reveal that Jupiter’s rapid growth disrupted the early solar system, creating rings where new planetesimals formed much later than expected. These late-forming bodies match the ages and ...
Nov. 12, 2025 Astronomers using the James Webb Space Telescope have uncovered a trove of complex organic molecules frozen in ice around a young star in a neighboring galaxy — including the first-ever detection ...
Nov. 12, 2025 Scientists have identified three Earth-sized planets orbiting two stars in the TOI-2267 system. Remarkably, planets transit around both stars — a first in astronomy. The system’s compact, cold ...
Nov. 11, 2025 New simulations suggest magnetic fields hold the key to forming black holes that defy known mass limits. When powerful magnetic forces act on a collapsing, spinning star, they eject vast amounts of ...
Nov. 10, 2025 XRISM’s observations of GX13+1 revealed a slow, fog-like wind instead of the expected high-speed blast, challenging existing models of radiation-driven outflows. The discovery hints that ...