What happens when a star stops fusing hydrogen?

Eventually the core of the star runs out of hydrogen. When that happens, the star can no longer hold up against gravity. Its inner layers start to collapse, which squishes the core, increasing the pressure and temperature in the core of the star. … At this point the star is called a red giant.

What happens when a star can no longer fuse hydrogen into helium in its core?

When hydrogen fusion can no longer happen in the core, gravity begins to collapse the core again. The star’s outer layers expand while the core is shrinking and as the expansion continues, the luminosity begins to increase. … After about 100 million years, the star fuses all its core helium into carbon.

What happens after the core fusion stops?

D. Helium fuses in a shell around the core. After core helium fusion stops, He fuses into carbon in a shell around the carbon core, and H fuses to He in a shell around the helium layer. … With each spike, convection dredges carbon up from the core and transports it to the surface.

What happens when a main sequence star first runs out of hydrogen in its core?

As the main sequence star glows, hydrogen in its core is converted into helium by nuclear fusion. When the hydrogen supply in the core begins to run out, and the star is no longer generating heat by nuclear fusion, the core becomes unstable and contracts. … All stars evolve the same way up to the red giant phase.

What do you think will happen when the star runs out of hydrogen to fuse Do you think other types of fusion are possible?

When our Sun runs out of hydrogen fuel in the core, it will contract and heat up to a sufficient degree that helium fusion can begin. … If your star is too low in mass, it will fuse hydrogen into helium only, and will never get hot enough to fuse helium into carbon.

What do stars burn after hydrogen?

helium
Stars on the main sequence burn by fusing hydrogen into helium. 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.

When the core of a star shrinks after hydrogen fusion stops?

When the core of a star shrinks after hydrogen fusion stops- the core cools and the star expands. Which of the following nuclear fuels does a one star use over the course of its entire evolution- hydrogen. warm starlike object that has too little mass to suppor fusion it its core.

What happens when fusion stops in 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.

When a star has fused most of its hydrogen and begins to collapse inward it is becoming a?

Eventually the core reaches a temperature of 10,000 degrees Kelvin, and it begins to look like a star when fusion reactions begin. When it has collapsed to about 30 times the size of our sun, it becomes a protostar.

What happens to a massive supergiant star when fusion ceases in its core?

Once the core fusion stops, however, gravity takes over and begins compressing the star. … If the star is at least 2.2 times more massive than our sun, helium-to-carbon ignition is a relatively gradual process. But for less hefty stars, it occurs with an explosive flash.

What happens when most of the hydrogen in the core is fused into helium in the stellar core?

Once a star has converted all the hydrogen in its core into helium, the core is no longer able to support itself and begins to collapse. It heats up and becomes hot enough for hydrogen in a shell outside the core to start fusion. … Eventually, the core becomes degenerate and the star expands onto the red giant branch.

When a star has used up all of the hydrogen in its core IT contracts but the rest of the star expands 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!

What happens to the core of a star after the planetary nebula stage?

what happens to the core of a star after a planetary nebula occurs? become a white dwarf. a stage when they have iron cores and cannot fuse any elements together to produce more energy. When this happens, the star explodes as a supernova.

What is the last fusion reaction to happen in the core of a high mass star?

Figure 1: Structure of an Old Massive Star.

The fusion of silicon into iron turns out to be the last step in the sequence of nonexplosive element production. Up to this point, each fusion reaction has produced energy because the nucleus of each fusion product has been a bit more stable than the nuclei that formed it.

When a low mass star runs out of hydrogen in its core it gets brighter Why?

In the core of the star, helium fusion occurs and creates degenerate electrons. Once the helium fusion is ignited, the core heats up very quickly and expands. This increases luminosity in the star. When a low-mass star runs out of hydrogen in its core, it gets brighter.

What happens to a star after it exhausts its core hydrogen quizlet?

What happens when a star exhausts its core hydrogen supply? Its core contracts, but its outer layers expand and the star becomes bigger and brighter.

How does hydrogen fusion in a high mass star differ from hydrogen fusion in a low mass star?

High mass stars go through a similar process to low mass stars in the beginning, except that it all happens much faster. They have a hydrogen fusion core, but much of the hydrogen fusion happens via the CNO cycle.

What happens to a low mass star when the hydrogen core stops fusing hydrogen into helium?

Low-Mass Stars fuse hydrogen into helium, the proton-proton cycle. … When the core hydrogen is used up and no more nuclear fusion occurs, the star’s outer stellar layers expand and the core shrinks. At this point, the star becomes a Subgiant Star . The star’s outer layers continue to expand and the star brightens.

What happens to the core of a high mass star after it runs out of hydrogen it shrinks and heats up it shrinks and downs helium fusion begins right away?

When the hydrogen fusion rate drops, the core’s temperature drops and so the thermal pressure drops. As a result, the core becomes less able to hold up the rest of the star’s weight. As the core gets squeezed; it (and the gas around it) shrinks in size. As this happens, the gas in the core and shell around it heats up.

What happens to a high-mass star when core helium fusion ceases quizlet?

It is only a matter of time until a helium core-fusion star converts al its core helium into carbon. When the core helium is exhausted, fusion will again cease, and the star will once again go out of energy balance.

What is different about a massive star’s lifetime during the hydrogen fusing phase where is this star on the HR diagram?

what is the first element that is converted in a star’s core? … what is different about a massive star’s lifetime during the hydrogen fusing phase? the phase is shorter because the star is so bright that it uses up fuel very fast. what are the last two elements that a massive star produces?

What happens after a high mass star leaves the main sequence?

Leaving the Main Sequence

High-mass stars become red supergiants, and then evolve to become blue supergiants. It’s fusing helium into carbon and oxygen. … When that happens, the outer layers of the star collapse in on the core.