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Where does hydrogen fusion occur when there is no hydrogen left in the core of a star?
Wiki User
∙ 12y ago
If there is no hydrogen left at the core of star then hydrogen fusion cannot occur. What happens in the core of a star before that happens is that helium begins to fuse, and then the other elements going up the Periodic Table until carbon. And then if the star explodes into a supernova, traces of the higher elements are fused as well.
Wiki User
∙ 12y ago
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Does a white dwarf star use hydrogen for energy?
No. A white dwarf is the remnant of a star in which fusion has stopped. There is no hydrogen left. All the energy left in a white dwarf is residual heat.
What happens to a star when the outward force of fusion is less than the inward force?
the star collapses in on itself, and usually when the fusion stops it is in the last stages of its life as a giant or supergiant and forms a white dwarf made of the carbon left over from the second stage of helium to carbon fusion from the core of the star that takes place after the hydrogen to helium fusion. after the white dwarf is formed it will eventually cool off into a black dwarf which is basically a carbon corpse of a star
What is the process that occurs in the Sun's core to produce so much energy?
Answer 1 The process that occurs in the Sun's core to produce so much energy is called nuclear fusion. Inside the Sun the temperature and pressure gets so high that substances fuse to from new substances. This process produces a large amount of heat, light and energy. Answer 2 Fusion. Isotopes of hydrogen bond together to form helium nuclei. Helium is a bit lighter than the hydrogen isotopes from which it is formed, and this difference, known as the mass defect, is matter converted into energy.
How is the evolution of a main-sequence star with less than 0.4 M fundamentally different from that of a main-sequence star with more than 0.4 M?
Main-sequence stars with mass less than 0.4M convert all of their mass into helium and then stop fusing. Their lifetimes last hundreds of billions of years, so none of these stars has yet left the main sequence. Core hydrogen fusion ceases when hydrogen in the core of a main-sequence star with more than 0.4M is gone, leaving a core of nearly pure helium surrounded by a shell where hydrogen fusion continues. Hydrogen shell fusion adds more helium to the star's core, which contracts and becomes hotter. The outer atmosphere expands considerably, and the star becomes a giant. Comments: I guess 0.4M means 0.4 solar masses. Usually the "M" has an extra little symbol next to it when it means this. Also I'm not sure that there's an exact number you can put on the division between these two types of star. I could argue with the details in the answer, but I have not got the time. Anyway the basic idea seems correct.
A large bright star whose hot core has used most of its hydrogen is a?
Red giant. The word "most" in the question isn't quite accurate. There is still a lot of hydrogen remaining in a star when the amount of helium becomes a problem. Hydrogen in the star is fused into helium, and the helium is at least roughly analogous to the ash in a wood fire; it is what's left over from the hydrogen fusion, and too much gets in the way. When the proportion of helium gets too high - above about 50% is enough - the helium begins to interfere with the hydrogen fusion process. Without enough new heat generated by fusion, the star begins to collapse under the influence of gravity. The compression increases the temperature, and when the pressure and temperature gets high enough, the helium "ash" in the core becomes helium "fuel" for the Red Giant phase.
Does a white dwarf star use hydrogen for energy?
No. A white dwarf is the remnant of a star in which fusion has stopped. There is no hydrogen left. All the energy left in a white dwarf is residual heat.
Who much hydrogen gas is left in the core of the sun?
Enough, it has been hypothesized, to maintain it in its present stable state for another 4.5 billion years from now, before it begins to readjust itself to its dwindling supply of fuel for fusion.
The sun is a enormous ball of?
Mainly Hydrogen more than 90%, but due to nuclear fusion, the hydrogen contineously bonds with other elements forming bigger elements, eventually fusion will cease to exist once the core of the sun reaches the stage where iron is the only element left to combine, then the sun will either explode or turn into a white dwarf, most likely the latter.
What happens to a star when the outward force of fusion is less than the inward force?
the star collapses in on itself, and usually when the fusion stops it is in the last stages of its life as a giant or supergiant and forms a white dwarf made of the carbon left over from the second stage of helium to carbon fusion from the core of the star that takes place after the hydrogen to helium fusion. after the white dwarf is formed it will eventually cool off into a black dwarf which is basically a carbon corpse of a star
What is the process that occurs in the Sun's core to produce so much energy?
Answer 1 The process that occurs in the Sun's core to produce so much energy is called nuclear fusion. Inside the Sun the temperature and pressure gets so high that substances fuse to from new substances. This process produces a large amount of heat, light and energy. Answer 2 Fusion. Isotopes of hydrogen bond together to form helium nuclei. Helium is a bit lighter than the hydrogen isotopes from which it is formed, and this difference, known as the mass defect, is matter converted into energy.
How is the evolution of a main-sequence star with less than 0.4 M fundamentally different from that of a main-sequence star with more than 0.4 M?
Main-sequence stars with mass less than 0.4M convert all of their mass into helium and then stop fusing. Their lifetimes last hundreds of billions of years, so none of these stars has yet left the main sequence. Core hydrogen fusion ceases when hydrogen in the core of a main-sequence star with more than 0.4M is gone, leaving a core of nearly pure helium surrounded by a shell where hydrogen fusion continues. Hydrogen shell fusion adds more helium to the star's core, which contracts and becomes hotter. The outer atmosphere expands considerably, and the star becomes a giant. Comments: I guess 0.4M means 0.4 solar masses. Usually the "M" has an extra little symbol next to it when it means this. Also I'm not sure that there's an exact number you can put on the division between these two types of star. I could argue with the details in the answer, but I have not got the time. Anyway the basic idea seems correct.
A large bright star whose hot core has used most of its hydrogen is a?
Red giant. The word "most" in the question isn't quite accurate. There is still a lot of hydrogen remaining in a star when the amount of helium becomes a problem. Hydrogen in the star is fused into helium, and the helium is at least roughly analogous to the ash in a wood fire; it is what's left over from the hydrogen fusion, and too much gets in the way. When the proportion of helium gets too high - above about 50% is enough - the helium begins to interfere with the hydrogen fusion process. Without enough new heat generated by fusion, the star begins to collapse under the influence of gravity. The compression increases the temperature, and when the pressure and temperature gets high enough, the helium "ash" in the core becomes helium "fuel" for the Red Giant phase.
Is a red giant a main sequence star?
No, a red giant is a star that has just left the hydrogen burning main sequence and begun the next step, burning helium. As helium undergoes fusion at a much higher temperature than hydrogen undergoes fusion, the star expands dramatically and as it expands its outer layers cool to red heat.
What is exploding during a super nova?
During a super-nova, a star explodes its outer-layers into a gaseous state. The massive explosion is triggered by the nuclear fusion in the core of the sun. The prossess of the elements fusion are hydrogen, helium, oxygen, carbon, iron, and uranium. Uranium is only found in hypergiant stars. When all of the fule is exausted, the star explodes each shell in order, until a white dwarf, nuetron star, or a black hole is left.
What is the process in which the nuclei of two atoms combine to form a larger nucleus?
It is called fusion. It is the process taking place on our sun, as two hydrogen atoms fuse together to form a helium atom and give off a small amount of energy while losing some mass.
Is it possible for the sun to become exhausted?
The expectation is that some day in the (to us) far future, most of the hydrogen in the sun will have been converted to helium (and higher weight atoms). At that point, the sun will be "exhausted" since the energy of the sun comes primarily from the fusion of the hydrogen - when there is no hydrogen left to fuse, the sun will have run out of "fuel".
How does a main sequence star get its energy?
Gravity. The star collapses until it reaches a temperature and pressure to ignite fusion. The pressure generated by the fusion opposes gravity and holds up the star until it runs out of fuel. This cycle can repeat until all that is left is nickel-iron, which cannot fuse. If the star is large enough, gravity can turn the burned out star into a black hole.
