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Gravitational collapse of a massive star, resulting in a Type II supernova. Gravitational collapse is the contraction of an astronomical object due to the influence of its own gravity, which tends to draw matter inward toward the center of gravity. [1] Gravitational collapse is a fundamental mechanism for structure formation in the universe.
Its core has undergone a contraction known as "core collapse" and it has a central density cusp with an enormous number of stars surrounding what may be a central black hole. [12] Home to over 100,000 stars, [11] the cluster is notable for containing a large number of variable stars (112) and pulsars (8), including one double neutron star ...
A planetary core consists of the innermost layers of a planet. [1] Cores may be entirely liquid, or a mixture of solid and liquid layers as is the case in the Earth. [2] In the Solar System, core sizes range from about 20% (the Moon) to 85% of a planet's radius .
When the core's mass exceeds the Chandrasekhar limit of about 1.4 M ☉, degeneracy pressure can no longer support it, and catastrophic collapse ensues. [10] The outer part of the core reaches velocities of up to 70 000 km/s (23% of the speed of light) as it collapses toward the center of the star. [11]
The core collapse of some massive stars may not result in a visible supernova. This happens if the initial core collapse cannot be reversed by the mechanism that produces an explosion, usually because the core is too massive. These events are difficult to detect, but large surveys have detected possible candidates.
Core collapse can refer to: The collapse of the stellar core of a massive star, such as the core collapse that produces a supernova; Core collapse (cluster), the dynamic process that leads to a concentration of stars at the core of a globular cluster
[26] [27] Further collisions and accumulation lead to terrestrial planets or the core of giant planets. If the planetesimals formed via the gravitational collapse of local concentrations of pebbles, their growth into planetary embryos and the cores of giant planets is dominated by the further accretions of pebbles.
Once a star has converted all the hydrogen in its core into helium, the core is no longer able to support itself and begins to collapse. It heats up and becomes hot enough for hydrogen in a shell outside the core to start fusion. The core continues to collapse and the outer layers of the star expand. At this stage, the star is a subgiant. Very ...