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Stellar Evolution

Stellar evolution is the life cycle of a star. Stars start out as clouds of gas and dust. The composition of the gas and dust will determine the stages that the star may go through.

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Why is suns core hotter?

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Asked by Wiki User

The corona is hotter than the photosphere because the sun's magnetic field carries energy upward from the surface and into the chromosphere and corona. The opposite effect is observed when the magnetic fields cause sunspots to form resulting in cooler surfaces.

What stage of stellar evolution is the sun experiencing at this time?

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Asked by Wiki User

Our Sun is currently on the Main Sequence stage of it's evolution.

Why some massive stars become neutron stars and other black holes?

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Asked by Wiki User

It depends on the mass of the star and how much of the star actually goes into the remnant.

Stars between 10 and 25 times the mass of the sun form neutron stars. Stars over 40 solar masses form black holes. Stars between 25 and 40 solar masses can form either depending on how much of the star is blown away during the supernova and how much falls back into the collapsing core.

The helium flash occurs at what stage in stellar evolution?

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Asked by Wiki User

As a G-type star fuses its hydrogen to helium, this helium will gather in the core. As a result, the core will contract under its own weight as hydrogen is being spent. The contraction causes an increased hydrogen fusion rate, increasing the temperature. When insufficient hydrogen remains in the core, the layers above are no longer supported by the outward pressure of radiation, and collapse on top of the core, causing it to contract further, and also initiating hydrogen fusion outside the core. At this point, the star leaves the main sequence, and becomes a red giant. At this stage, the core of the giant may reach critical density for helium fusion to initiate. Since the core is composed of mostly degenerate matter at this stage, there is no regulation of the fusion rate. Also, degenerate matter is less opaque to the energies produced than non-degenerate matter, so conducts them better.

Ehr, to summarize: the helium flash occurs during the red giant stage of G-type stars.

What is a star life cycle that is accurate?

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Asked by Wiki User

Stars form when enough hydrogen accumulates to cause enough internal pressure and heat to make the ball of hydrogen glow from the fusion of hydrogen to form helium. Depending on the size and temperature of the new star, it will fall along the HR Diagram as a class O,B,A,F,G,K or M star. Class O stars are very big and very hot, giving off blue/white light. Class M stars are small, cool red dwarf stars. Our sun is a class G star, a small star which burns moderately and is yellow.

Depending on the mass of the star, it will burn at different rates. Class O and B stars, although large, burn very fast because they are so hot. Class M stars, being small and cool, can burn for many millions of years longer.

Eventually, all stars run out of fuel and begin to collapse on themselves. What happens next depends on the type of star.

Large, hot stars will explode in a supernova, ejecting their entire blanket of gases into space and leaving behind a small core which will be a pulsar (neutron star), or even a black hole.

Medium stars like our sun will swell their outer layers to become Red Giants (such as Betelguese in Orion). This phase will last for a few million years until the core finally cannot support the outer layers any longer. To give you an idea of size, our sun will eventually send it's outer layers as far out as to engulf Mars.

Once these moderate Red Giants run out of fuel, they collapse and form a white dwarf star, which will be the end result of our sun. After billions of years, they will cease to glow and become black dwarfs. (Do not confuse this with black holes..completely different).

Small red dwarf stars will puff out outer layers in a planetary nebula, but will not have enough energy to explode. They will eventually become small black dwarf stars as they lose their energy and can no longer burn.

This is very brief because this is a very complex process, but I hope this helped.

The point in stellar evolution when a star has used up all its fuel and is radiating away its remaining thermal energy as light?

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Asked by Wiki User

White dwarf stage. Note that not all stars reach this stage. Some stars experience runaway criticality and go supernova. Also, white dwarf stars in binary systems can still go nova if they are acquiring hydrogen from their partner.

Why is stellar evolution important?

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Asked by Wiki User

hydrogen is what stars are mostly made Being the reservoir from which new stars are born in the Galaxy, interstellar matteris of fundamental importance in understanding both the processes leading to the formation of stars, including the solar system, and ultimately the origin of life in the universe. Stellar evolution stellar evolution is a necessary consequence of the physical theory of stellar-structure, which requires that the luminosity, temperature, and size of a star must change as its chemical composition changes because of thermonuclear reactions.

ken mendoza

PHIL.....

What is the final stage of stellar evolution?

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Asked by JamesMcQueen446

Supernovae are caused by the gravitational collapse of massive stars. When the material in the core of the star reaches the density of an atomic nucleus, nuclear forces (actually "neutron degeneracy pressure," but that's a whole new topic) balance gravity and the collapse is suddenly halted. This creates a shock front between the material that has stopped and the material that is still falling inward. The shock front moves moves outwards (only direction it can go, think about it) through the star and explodes as a supernova.

So, to answer your actual question, that small dense remnant is called a neutron star. If the neutron star can steal some material from somewhere (either another star or perhaps the remains of its parent star), it might become so big that gravity becomes dominant again, and will collapse, this time into a black hole.

Explain the life cycle of a star?

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Asked by Wiki User

Stars have a typical path of development. The details of this path depend on their mass. Smaller stars, like our sun, will gradually grow hotter, until they become a red giant. Ultimately they will shed their outer layers, and a white dwarf remains. Much more massive stars might go nova in stead.

Why are star clusters ideal 'laboratories' for stellar evolution?

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Asked by Wiki User

Star clusters are ideal for figuring out certain things of stellar evolution because every star in a cluster is made of basically the same material and therefore has the same composition, they are basically at the same distance from the earth, and they all basically move the same way.

This is ideal because it can be tough to determine whether some stars are closer or farther away (brightness would make you think that a brighter star is closer but this is not always the case) but looking at 2 stars in the same cluster, if one looks brighter, it actually is!

These clusters make it easy for astronomers to see how stars grow up!

Stellar evolution is the life cycle of a star A cycle suggests that upon death of a star another star is born How is this possible?

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Asked by Wiki User

Although at the end of a stars life - another "type" of star is born, they are different to the "normal" type of star and are "star" in name only. Most "remnants" of stars should be classed as degenerate stars.

Our Sun (a star) will first turn into a red giant star [See related question] and then a white dwarf star [See related question]

What is the life cycle of a sunlike star?

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Asked by Wiki User

G-type stars, like the sun, will generally go through their main sequence, growing brighter all the time, until they expand to red giants, followed by a helium flash (or possibly several flashes), followed by the shedding of the outer layers of the star, at which time a slowly cooling white dwarf remains, which should, given enough time, cool enough to become a black dwarf.

What is the correct sequence for stellar evolution?

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Asked by Wiki User

Stellar evolution states that stars are powered by a hydrogen fusion reaction. When a star has burned up its hydrogen, this reaction runs out, and its core will contract and heat up causing the hydrogen shell to ignite. This causes the star to expand into a giant star. Depending on the solar mass of the star, it will evolve into different objects. If its mass is in the 0.3 to 3 range, its core, now fusing helium will degenerate before the helium has a chance to ignite, and the explosion that results will be absorbed into the star itself. A star with a mass less than 0.4 will evolve into a white dwarf. If its mass is between 0.4 and 0.3, it will become a red giant and then burn out into a white dwarf. Stars that are more massive will collapse explosively as a super nova, and if it is larger than 25 stellar masses, it will be a neutron star.

What causes the collapse of a star?

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Asked by Wiki User

The collapse of a star is based on its age. When it runs out of "Fuel" its inside contracts as the outside expands. it can then super nova or collapse into a tiny star.

Why will a star with a large mass radiate more energy into space and appear hotter and brighter than a star with a smaller mass?

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Asked by Wiki User

Because the larger mass means more core pressure, making fuel (hydrogen turning into helium) burn faster and more frequently, resulting in a hotter, brigher star. A small mass star has less fuel and internal pressure, so it generates less light and is red in color. A medium star like our sun burns moderately, and is yellow.

The H-R Diagram places these stars in spectral classes, from biggest and hottest to smallest and dimmest, and the orders are O, B, A, F, G, K and M. We are a type G star.

Think of a fire; the more fuel you put on it, the hotter and brighter it blazes and it can become white-hot if it is a very intense fire. As the ashes burn down, the fire is smaller, dimmer and the coals appear red, which is cooler.

The principle is the same with stars; the bigger and hotter they are, the brighter they burn but they have shorter lives than do moderate and small stars.

In the life cycle of a star what stage occurs immediately before a supernova explosion?

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Asked by Wiki User

The remnant core of a star that becomes a supernova will normally be a neutron star, or possibly a pulsar (a rapidly spinning neutron star). The largest of stars would theoretically create a black hole, a singularity containing all of the core's mass at a single point and preventing even light from escaping its massive gravity.

Why are all elements heavier then iron created during a supernova?

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Asked by Wiki User

The rapid collapse of the star compresses atoms together and may cause nuclear fusion and make heavier elements.

What two elements are involved in nuclear fusion reaction?

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Asked by Wiki User

In the sun it is just protons, which are hydrogen nuclei. On earth experiments are using two isotopes of hydrogen, deuterium and tritium. These are still the same element, hydrogen, just two different isotopes.

What is the next stage in the life of a lower-mass main-sequence star?

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Asked by Wiki User

white dwarf. unless you count black dwarf of which none have been observed, only theorized.

What would happen if a gamma ray burst hit the earth?

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Asked by Wiki User

The atmosphere would be fried and the Earth would disentegrate.

What are the Stages of a star?

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Asked by Wiki User

nebula then protosar then red dwarf, yellow star or a blue giant then a red giant then a red super giant then eithr a white dwarf or a supernova from the supernova a black hole or a neutron star if it is a white dwarf it turns into a black dwarf then a black hole

  • Nebula
  • Baby star
  • Star
  • Giant or supergiant
  • White dwarf
  • Black dwarf

Why do astronomers study a group of stars rather than just one star when studying life cycles?

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Asked by Wiki User

they study the stars the same reason we study most things, to understand.

relly? they studly them because space may hold the awnser to our meaning, how we were created, and how we will end.

How many elements from the sun make up starch?

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Asked by Wiki User

The elements of starch are carbon, hydrogen, and oxygen.