A Star's Life, (Full Explanation)

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Discussion Overview

The discussion revolves around the various stages of a star's life cycle, from its formation to its eventual fate. Participants explore the processes involved in stellar evolution, including the conditions necessary for fusion, the different types of stars, and the outcomes of stellar explosions. The scope includes theoretical aspects, conceptual clarifications, and references to relevant diagrams and literature.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Meta-discussion

Main Points Raised

  • One participant outlines a detailed sequence of events in a star's life, starting from hydrogen gas clumping together due to gravity.
  • There are questions about the mechanisms of light emission during the formation of a proto-star and the conditions required for hydrogen nuclei to fuse.
  • Some participants propose that the mass of a star influences its lifespan, with low-mass stars potentially living for billions of years and high-mass stars for millions.
  • Concerns are raised about the processes leading to red giants, supernovae, and the formation of white dwarfs, neutron stars, and black holes.
  • There is mention of binary star systems and the potential interactions between different types of stars, including the creation of pulsars and supernovae from collisions.
  • References to the Hertzsprung-Russell diagram are made, suggesting it illustrates the various paths stars can take as they evolve.
  • Several participants suggest that the original post is too lengthy and complex, advocating for breaking it down into smaller, more manageable questions.
  • Multiple sources and texts are recommended for further reading on stellar evolution and astrophysics.

Areas of Agreement / Disagreement

Participants express differing views on how to approach the discussion, with some advocating for a breakdown of questions while others emphasize the complexity of stellar evolution. There is no consensus on a single approach to answering the original post's inquiries.

Contextual Notes

The discussion highlights the complexity of stellar evolution, with many assumptions and conditions left unaddressed. The exact processes and outcomes of stellar life cycles remain partially understood, and the number of possible evolutionary tracks for stars is not definitively known.

Who May Find This Useful

This discussion may be of interest to individuals studying astrophysics, astronomy, or anyone curious about the life cycles of stars and the processes involved in stellar evolution.

menergyam
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Can someone explain all the known paths a star can take from its birth to its death?
This is what I know so far. Please correct me or add things where they need to be in the list

1) Hydrogen gas, clumps together by gravity.

2) Hydrogen atoms bump against each other and these collisions cause a rise in temperature.

3) The temperature of the gas gets very high. Also the pressure gets high too from gravity
a) Electrons are excited by the increase in pressure and temperature, collisions with lesser energtic electrons causes a change in energy, thus light is emitted.
(Need explanation) for other reasons why light is emitted.
b) A proto-star is created. A star is in the development stage.
c) If a star is not born, it turns into a brown dwarf.

4) A critical temperature and pressure needs to be reached. (Need explanation)
a) (Need explanation) Why does Hydrogen nuclei fuse exactly? I will provide a reason of what I think in part 4b.
b) Fusion occurs when the force of gravity overcomes the electromagnetic force of the nuclei. Then the two nuclei come close enough for the strong force to take over.
Somehow the mass of the the two nuclei is reduced, the change in mass = energy output. (Need explanation)

5) Fusion occurs between two nuclei, energy is released, other nuclei start to fuse. Chain
reaction occurs. A star is born.

6) Depending on the initial amount of hydrogen gas, the star's life will be different.
a) If the star's mass is low, then it will live for billions or maybe trillions of years. (Need explanation)
b) If the star's mass is high, then it will live for millions of years. (Need explanation)

6a) This star will fuse hydrogen nuclei an neutrons into a helium atom. (Need explanation) for where neutrons come from.
I) Fusion rate decreases over time, less and less hydrogen nuclei. Graivty increases.
II) The force of gravity exceeds the outwards force caused by fusion energy. Net force is inwards. The inwards force increaes at a certain rate.
III) As the inwards force increases the outer most layer of helium and if there is some hydrogen gas expand. Star turns into a red giant.
IV) Eventually hydrogen and helium gas that were far enough away from the center of the star escape. Class 1 Supernova.
V) The rest of gas, mainly helium now are subjected to a strong gravatational force.
VI) (Need explanation) Somehow less massive stars can't fuse helium.
VII) Star somehow turns into a white dwarf, white dwarfs don't collapse because of electron repulsion. (Need explanation)
VIII) Something happens and the white dwarf ceases to exit anymore. (Need explanation)

6b) This star will fuse hydrogen nuclei and neutrons into a helium atom. This star is massive so, it will be able to fuse helium and more.
I) The star's internal structure is analogous to an onion because of different elements with different masses.
II) The star fuses more and more nuclei, and different elements are made within the star. The most massive elements are in the center, iron and the lightest element are near the surface, hydrogen.
III) Iron nuclei don't fuse because it is not energy benefitial (Need explanation).
IV) The iron core becomes non fusable and more and more iron is created from the fusion of the other elements.
V) The iron core collapses and becomes very dense, because of gravity? (Need explanation)
VI) The other layers of elements are released from the sudden collapes of the iron core. Class 2 Supernova.
VIII) The iron core becomes compressed, and the electrons that are around somehow fuse with the protons in the iron.(Need explanation) The star becomes a neutron star.
IX) A neutron star somehow becomes a blackhole, (Need explanation)

7) So in the end, you end up with white dwarfs, neutron stars, and black holes. (Need explanation) to what happends to the white dwarf, neutron star or black hole.
a) White dwarfs somehow cease to exist
b) neutron stars somehow disappear
c) Black holes decay from Hawking radiation

8) Stars may have partners, binary stars. There are different possibilites.
a) If two neutron stars orbit each other, they create gravatiational fields. Light is emitted, and if light is directed towards earth, we see this light as pulses, we call this pulsars. Once the neutron stars collide, they explode, another super nova?
b) If two white dwarfs orbit each other, they create ... (Need explanation)
c) If a white dwarf orbits a neutron star, the white dwarf would collide into the neutron star because it is more massive... another super nova?
d) When a white dwarf or neutron star collides into other stars, depending on the masses of the celestrial bodies, a super nova occurs...?
e) What other possibilites are out there?

9) Explosions from stars release different elements, and during a supernova, higer elements are created (Need explanation)

10) This concludes the life of a star.
 
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I might suggest breaking up your questions into separate topics. You are asking approximately 15 questions about stellar life. The proper way to answer your question is to write you a book on the subject. Break up the questions, and it will be easier to solve your riddles.

Cheers,
--Jake
 
I am not asking one person to answer my long set of questions. I was expecting one person to tackle one question at a time. And I was expecting different people to answer different parts of my questions. Now I realize, since the post is so long, I think people just don't want to read it.
 
You should look into the Hertzsprung-Russell diagram, which shows the entire gamut of possible stars. As stars age, they move from place to place on the diagram. As a result, you can draw a curve, a "track," on the H-R diagram representing any specific star's life.

Many different tracks have been computed and can be visualized on the diagram.

The number of possible tracks is technically infinite -- even very small variations in initial mass can result in significantly different tracks on the H-R diagram. In practice, though, stars generally move along a relatively small number of well-understood categories of tracks, and that's probably the answer you're looking for. The exact number of such categories is not known, because stellar evolution is not completely understood at this time.

http://en.wikipedia.org/wiki/Hertzsprung-Russell

- Warren
 
Thanks a lot. Sorry for the long post.
 
One should be able to find a text in astronomy and astrophysics, which discusses the evolution of stars, e.g. Introduction to Modern Astrophysics, An (2nd Edition) by Bradley W. Carroll and Dale A. Ostlie, or more specifically An Introduction to Modern Stellar Astrophysics by Bradley W. Carroll and Dale A. Ostlie.

There are many texts, which are devoted to stellar evolution (type "Stellar Evolution",books into Google or go to any bookseller website and search on "Stellar Evolution")

Principles of stellar evolution and nucleosynthesis By Donald D. Clayton

There are class notes on-line - http://cass.ucsd.edu/public/tutorial/StevI.html

http://chandra.harvard.edu/edu/formal/stellar_ev/

http://www.umich.edu/~gs265/star.htm
 
menergyam said:
I was expecting one person to tackle one question at a time. And I was expecting different people to answer different parts of my questions. Now I realize, since the post is so long, I think people just don't want to read it.

Even if a person did tackle this in one shot, it will be far too much explanation where you could just easily read it on a book dealing with the topic. People are going to read the post, just they aren't going to tackle one question at a time. There are different types of of a stars, not just one type of star, which have their their unique cycle of life and characteristics.
 
Thanks a lot Everyone!
 
  • #10
I agree with these replies. It is unfortunate that the explanations to your post can easily span more than an entire course worth of material. Books are fantastic places to get this information. However, like other people here have suggested, you should focus on one question at a time. It will help keep you focused.

On another note, I am a huge fan of stellar structure and evolution.
 

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