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When a star exhausts its nuclear fuel and can no longer undergo fusion, it will undergo significant changes depending on its mass. A low to medium-mass star, like the Sun, will expand into a red giant and eventually shed its outer layers, forming a planetary nebula, while the core will collapse into a white dwarf. More massive stars will explode in a supernova, leaving behind a neutron star or a black hole, depending on their remaining mass.
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A massive star with what element does nuclear fusion stop?
A massive star with iron in its core will stop nuclear fusion, leading to its collapse and eventual explosion as a supernova. Iron is the element at which fusion becomes endothermic, meaning energy is no longer released in the process.
What is old dead small star?
Technically a dead star is when a star no longer undergoes nuclear fusion. Depending on the mass of the original star this will either be a white dwarf, neutron star or black hole. These are called stellar remnants.
What element is produced by fusion in the star before a super nova occurs?
Before a supernova occurs, a massive star undergoes fusion to produce iron in its core. As fusion progresses, the star creates heavier elements up to iron, which cannot release energy through fusion. When the core becomes predominantly iron, it can no longer support the star against gravitational collapse, leading to a supernova explosion.
The last two elements that a massive star produces are hydrogen and helium why is this the last reaction?
Hydrogen and helium are the lightest and most abundant elements in the universe. In the core of a massive star undergoing nuclear fusion, hydrogen and helium are fused into heavier elements like carbon, oxygen, and iron. Once the star reaches the stage where it can no longer sustain fusion reactions to produce heavier elements, hydrogen and helium remain as the last elements in its core before it undergoes a supernova explosion.
In stars more massive than the Sun fusion continues until the core is almost all?
Iron. Iron is the heaviest element that can be produced through nuclear fusion in a star, and once the core of a massive star is mostly composed of iron, it can no longer sustain fusion reactions. This triggers its collapse and ultimately leads to a supernova explosion.
When do you say that stars are dead?
When the star no longer undergoes nuclear fusion.
Reaction dead star?
A dead star, also known as a white dwarf, is the remnant core of a star that has exhausted its nuclear fuel. It no longer undergoes fusion reactions and gradually cools over billions of years. Sometimes, if it is part of a binary system with a companion star, it can reignite and explode in a supernova.
What is the life cycle of a star bigger than the sun?
A star larger than the Sun, often referred to as a massive star, begins its life in a nebula, where it undergoes nuclear fusion, converting hydrogen into helium. As it exhausts its hydrogen fuel, it expands into a red supergiant and eventually undergoes fusion of heavier elements. Once it can no longer support fusion, the core collapses, leading to a catastrophic supernova explosion, while the outer layers are expelled. The remnant core may become a neutron star or, if massive enough, collapse further into a black hole.
A massive star with what element does nuclear fusion stop?
A massive star with iron in its core will stop nuclear fusion, leading to its collapse and eventual explosion as a supernova. Iron is the element at which fusion becomes endothermic, meaning energy is no longer released in the process.
What nuclear reaction is the energy source of a white dwarf?
The energy source of a white dwarf is primarily from nuclear reactions involving the fusion of helium nuclei, also known as the triple-alpha process. This process converts helium into heavier elements like carbon and oxygen, releasing energy in the form of heat and light. As a white dwarf no longer undergoes significant nuclear fusion, the energy it radiates gradually comes from stored thermal energy.
What is the phase of a star called where it simply cools and fades away?
The phase of a star where it cools and fades away is called the white dwarf phase. During this stage, the star no longer undergoes nuclear fusion and gradually loses its heat and brightness over billions of years.
Is white dwarf a dead star?
Yes - in the sense that it no longer produces energy. In other words, the star has run out of fuel for nuclear fusion.
What is old dead small star?
Technically a dead star is when a star no longer undergoes nuclear fusion. Depending on the mass of the original star this will either be a white dwarf, neutron star or black hole. These are called stellar remnants.
What will a less massive supernova become?
Supernovae refer to the sudden expulsion of mass and energy when a large star can no longer fuse material matter. It results from the core collapsing into itself because it no longer has nuclear fusion to counteract it's own gravity and it's too dense for electron degeneracy to prevent collapse. .
What element is produced by fusion in the star before a super nova occurs?
Before a supernova occurs, a massive star undergoes fusion to produce iron in its core. As fusion progresses, the star creates heavier elements up to iron, which cannot release energy through fusion. When the core becomes predominantly iron, it can no longer support the star against gravitational collapse, leading to a supernova explosion.
The last two elements that a massive star produces are hydrogen and helium why is this the last reaction?
Hydrogen and helium are the lightest and most abundant elements in the universe. In the core of a massive star undergoing nuclear fusion, hydrogen and helium are fused into heavier elements like carbon, oxygen, and iron. Once the star reaches the stage where it can no longer sustain fusion reactions to produce heavier elements, hydrogen and helium remain as the last elements in its core before it undergoes a supernova explosion.
How long does it take for spent nuclear fuel to become safe?
This takes around 6.000.000 years but it could take longer depending on the amount of nuclear fuel spilt.
