What is the life cycle of a star?

Answer 1

The life cycle of a star depends on it's mass. Although all stars go through a main sequence, what happens after is very different for small stars and large stars.

A protostar is a dense pocket of gas that collapses inward due to its own gravity, getting hotter as it squeezes inward. All stars are "born" from nebulas, which are clouds of gas and dust. A protostar becomes a star when the pressure and temperature reach a point where the hydrogen in its core begins to fuse to helium, releasing tremendous energy. A star that fuses hydrogen is said to be in its main sequence.

Brown dwarfs are very small protostars that never have enough mass and gravity to initiate fusion; red dwarfs are stars that have just enough mass to initiate fusion but produce very little energy; red dwarfs take tens or hundreds of billions of years to burn through their hydrogen fuel before they simply cool down and die.

The main sequence of slightly larger stars, such as our sun, lasts for about ten billion years. When the hydrogen in the star runs out (converts to helium), the star sputters and goes through another round of collapse, which increases the density in the core and starts the fusion of helium into heavier elements. The extra energy from helium fusion causes the outer layers to puff out, creating a red giant. Eventually, the outer layers drift away, leaving only the tiny core, which is known as a white dwarf.

Bigger stars burn through their hydrogen in tens or hundreds of millions of years, then go through several cycles of collapse and re-ignition with ever-heavier elements, forming supergiant stars. When these stars start generating iron in their cores, they die horribly because fusing iron absorbs energy instead of releasing it; this quickly stops the core's energy output, causing the rest of the star to collapse inward and explode as a supernova.

A neutron star, which is an extremely dense ball of atomic nuclei, or a black hole could form from the collapsed core.

Sign up to view the whole answer

By signing up, you agree to our Terms of Service and Privacy Policy

Sign up with email
Answer 2

A star's life cycle starts with the protostar, which is formed from a collapsing cloud of gas and dust. The protostar then goes through the main sequence phase, where it fuses hydrogen into helium in its core to produce energy and maintain stability. After the main sequence phase, a star can go through different stages and durations, depending on its mass, and can become a red giant, white dwarf, neutron star, or black hole.

Sign up to view the whole answer

By signing up, you agree to our Terms of Service and Privacy Policy

Sign up with email
Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

Not the question you need?

Drag image here or click to upload

Or press Ctrl + V to paste
Answer Background
HIX Tutor
Solve ANY homework problem with a smart AI
  • 98% accuracy study help
  • Covers math, physics, chemistry, biology, and more
  • Step-by-step, in-depth guides
  • Readily available 24/7