Core Collapse: Catastrophic gravitational infall of the center of a star when it no longer can generate sufficient pressure to maintain hydrostatic equilibrium.
The core collapses, then rebounds, bringing with it a shock wave. The outer contents of the star fly apart at 10,000 miles per second, performing some secondary fusion due to the immense heat of the explosion.
The core collapse in the dying star releases a vast amount of gravitational potential energy, sufficient to blow away all the outer parts of the star in a violent explosion, and the star becomes a supernova.
The core collapsed very quickly from a size close to that of the Sun's to only about 20 km, so there is a gap in the support of the rest of the star. What support? - there is NO SUPPORT! Nothing is holding up the rest of the star.
As the core collapses, the outer layers have nothing to support them, and they collapse inwards, too. Once the density reaches about 1015 gm/cm3, the collapse is again halted. This is about the density of an atomic nucleus.
5. Core collapse in a massive star is eventually stopped by _____ degeneracy pressure. (Hint)
6. A Type _____ supernova occurs when the core of a massive star implodes and rebounds. (Hint) ...
Since the core collapse supernova mechanism itself is imperfectly understood, it is still not known whether it is possible for a star to collapse directly to a black hole without producing a visible supernova, ...
When a stellar core collapses, the pressure causes electron capture, thus converting the great majority of the protons into neutrons.
The term "supernova" is derived from "nova" in that the supernova is vastly brighter, no matter that the mechanism of the core collapse of a supergiant is completely different from the mechanism of nova production.
The core cools, drawing heat from its surroundings to power the fusion; the outward radiative pressure, which had supported the star for many millions of years, ceases and the star undergoes free fall gravitational core collapse until it reaches ...
We have already discussed Type II SN which result from the core collapse at the final stage in the evolution of a massive star.
They are all examples of core collapse events with most arising due to a massive progenitor star exhausting its core fuel. Perhaps the best known example of this was Supernova 1987A.
The centre of the core collapses quickest and hydrogen 'shell burning' commences in a shell layer around the core once the layer reaches sufficient density and temperature.
The neutrinos formed when the neutron core is created fly away from the stiff core, carrying most of the energy (over 99%) from the core collapse away with them. Some energy (less than1%) goes into driving the gas envelope outward.
In the final stages before the core collapse leading to a supernova, a massive star burns 1.4 solar masses of silicon into iron in about 2 DAYS.
When the core collapses the entire star collapses. The surface of the star falls down unti l it hits the now incredibly dense core. It then rebounds off the core and blows apart in a type IIa supernova.
In the case of a Sun-like star, the core collapses into a dense white dwarf, while the outer layers are gently blown away to form a planetary nebula.
The core collapse phase of a supernova is an almost unimaginably dense and energetic event. It is so dense that no known particles are able to escape the advancing core front except for neutrinos.
After enough iron in the core is accumulated, within one hundredth second, the inner core collapses and heats up dramatically. All fuel, if not burnt up yet, will fuse to iron and nickel. The outer core will also collapse with the inner core.
It takes less than a day for the silicon to fuse into iron; the iron core gets hotter and hotter and in less than a second the core collapses.
With these changes, different nuclear processes occur; fusion now produces heavier elements (this temporarily stop the core's shrinking).
Eventually this core collapses (in an instant).
Not only does tidal shock strip off the outer stars from a globular cluster, but the increased evaporation accelerates the process of core collapse.
See also
*List of globular clusters
*Plummer model
*Relaxation time
References ...
The outer layers of a supernova are irradiated by neutrons produced as the core collapses to form a neutron star. The neutrons react with atomic nuclei to form heavier elements. [Silk90]
Irregular Galaxy ...
(b) Exposure to an intense flux of fast neutrons or to ionizing radiation. The outer layers of a supernova are irradiated by neutrons produced as the core collapses to form a neutron star.
Such exotic mechanisms as pair-production instability or reverse nucleosynthesis can drive core collapse in various mass ranges.
An extreamly massive star would undergo catastropic core collapse, exploding violently and rapidly as a supernova, creating even heavier elements, and spewing much of the stellar material into space.
 See also: Collapse, Star, Core, Supernova, Light
  
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