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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 ...
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.
When core collapse occurs in a star with a core at least around fifteen times the Sun's mass (M ☉) — though chemical composition and rotational rate are also significant — the explosion energy is insufficient to expel the outer layers of the star, and it will collapse into a black hole without producing a visible supernova outburst.
These super-AGB stars may form the majority of core collapse supernovae, although less luminous and so less commonly observed than those from more massive progenitors. [118] If core collapse occurs during a supergiant phase when the star still has a hydrogen envelope, the result is a type II supernova. [121]
Venus’ core is believed to be iron-nickel, similarly to Earth. Mars, on the other hand, is believed to have an iron-sulfur core and is separated into an outer liquid layer around an inner solid core. [20] As the orbital radius of a rocky planet increases, the size of the core relative to the total radius of the planet decreases. [15]
The possibility of direct collapse into black holes of stars with core mass > 133 M ☉, requiring total stellar mass of > 260 M ☉ has been considered, but there may be little chance of observing such a high-mass supernova remnant; i.e., the lower bound of the upper mass gap may represent a mass cutoff. [11]
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) ...
In the core of a star such as the Sun, gravitational pressure is balanced by the outward thermal pressure from fusion reactions, temporarily halting gravitational compression. At the center of a planet or star , gravitational compression produces heat by the Kelvin–Helmholtz mechanism .