What happens when all of the hydrogen is used up inside a star?

Once a star has exhausted its supply of hydrogen in its core, leaving nothing but helium, the outward force created by fusion starts to decrease and the star can no longer maintain equilibrium. The force of gravity becomes greater than the force from internal pressure and the star begins to collapse.

What will happen first when most of its hydrogen has been used up by star?

Hydrogen is the element that requires the lowest temperature and pressure to be subject to nuclear fusion, so it will fuse (into helium) first.

What happens when a star uses up all its energy?

Stars must burn through fuel and release energy to prevent them from collapsing in on themselves, but this cannot go on forever. Eventually the star will run out of its essential fuel entirely, resulting in its explosive end.

When hydrogen fusion in a star stops the core contracts but the surface expands explain why?

The star as a whole expands because the energy transport cannot keep up with the shell’s increasing energy generation rate, so the thermal energy is trapped in the star and builds up, pushing the surface outward. You just studied 21 terms!

Which of the following is a star that has used up its hydrogen supply in the core?

A red giant is a star that has used up its hydrogen supply in the core and switched into the thermonuclear fusion of hydrogen in the shell surrounding the core.

Are All stars hydrogen?

All stars are composed of hydrogen and helium, and depending on age and generation, they may have varying amounts of heavier elements.

Do all stars make energy through fusion?

The energy source for all stars is nuclear fusion. Stars are made mostly of hydrogen and helium, which are packed so densely in a star that in the star’s center the pressure is great enough to initiate nuclear fusion reactions.

What elements do stars burn?

Stars shine by burning hydrogen into helium in their cores, and later in their lives create heavier elements. Most stars have small amounts of heavier elements like carbon, nitrogen, oxygen and iron, which were created by stars that existed before them.

Why does hydrogen fusion eventually move away from the core of a star?

A star remains on the main sequence as long as there is hydrogen in its core that it can fuse into helium. So far we have assumed that a star on the main sequence maintains a constant energy output. Eventually the hydrogen fuel in the core runs out and fusion stops, shutting off the outward radiation pressure.

What happens when a star runs out of hydrogen fuel?

When the core runs out of hydrogen fuel, it will contract under the weight of gravity. However, some hydrogen fusion will occur in the upper layers. As the core contracts, it heats up. This heats the upper layers, causing them to expand. As the outer layers expand, the radius of the star will increase and it will become a red giant.

Why do large stars burn more fuel than small stars?

Large stars tend to have higher core temperatures than smaller stars. Therefore, large stars burn the hydrogen fuel in the core quickly, whereas, small stars burn it more slowly. The length of time that they spend on the main sequence depends upon how quickly the hydrogen gets used up.

How do stars expand and contract like the Sun?

Stars Like the Sun. When the core runs out of hydrogen fuel, it will contract under the weight of gravity. However, some hydrogen fusion will occur in the upper layers. As the core contracts, it heats up. This heats the upper layers, causing them to expand. As the outer layers expand, the radius of the star will increase and it will become…

What determines how long a star stays on the main sequence?

Therefore, large stars burn the hydrogen fuel in the core quickly, whereas, small stars burn it more slowly. The length of time that they spend on the main sequence depends upon how quickly the hydrogen gets used up.