Unveiling the Mystery: The Birth of Stars and the Role of Nuclear Fusion

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In summary: It also seems like the velocity of the mass would make a difference. Perhaps if the star forms within a large-scale current or flow of matter the force of that “wind” can inject more mass than in a more tranquil environment.
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TShock
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Why are some stars larger than others? It is my understanding that hydrogen collapses due to gravity into a sphere and when a critical mass is achieved nuclear fusion occurs. Since the critical mass for this to happen is a constant shouldn't all stars be relatively the same size since a star doesn't collect any more mass once fusion starts?
 
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  • #2
TShock said:
Since the critical mass for this to happen is a constant shouldn't all stars be relatively the same size since a star doesn't collect any more mass once fusion starts?

I don't think this part is true. Why would a star stop collecting mass just because fusion started?
 
  • #3
CaptainQuasar said:
I don't think this part is true. Why would a star stop collecting mass just because fusion started?

The force of matter being ejected by Sol would stop any new hydrogen from being collected. The same reason why Mercury has no atmosphere or what would happen to Earth's atmosphere if Sol turns into a red giant.
 
  • #4
TShock said:
The force of matter being ejected by Sol would stop any new hydrogen from being collected. The same reason why Mercury has no atmosphere or what would happen to Earth's atmosphere if Sol turns into a red giant.

Hmmm. Well, I'm not an astrophysicist or a physicist of any kind, but my thoughts would be: is this true of all stars or just Sol-like ones? Is it really omnidirectional so that mass can't approach from any direction? And would this be true independent of the astrophysical environment, like would it still happen within a dense dust cloud? And does it really happen immediately as soon as fusion starts, or is there a gap in time between fusion and repellent force, during which the inflow of matter from the astrophysical environment will determine the eventual mass of the star?

It also seems like the velocity of the mass would make a difference. Perhaps if the star forms within a large-scale current or flow of matter the force of that “wind” can inject more mass than in a more tranquil environment.
 
  • #5
well I guess either no one knows or my question was so incredibly stupid no one could be bothered to answer it. Thanks to those that did post replys.
 
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Related to Unveiling the Mystery: The Birth of Stars and the Role of Nuclear Fusion

1. How are new stars formed?

New stars are formed through a process called nuclear fusion, in which hydrogen atoms fuse together to form helium. This process requires high temperatures and pressures, which can be found in the dense cores of molecular clouds.

2. What triggers the formation of new stars?

The formation of new stars is triggered by the collapse of a dense region within a molecular cloud. This collapse can be caused by shockwaves from nearby supernovae, gravitational interactions with other clouds, or disruptions from spiral arms in galaxies.

3. How long does it take for a new star to form?

The time it takes for a new star to form can vary depending on the size and density of the molecular cloud, but on average it can take around 100,000 to 1 million years.

4. What determines the size and mass of a new star?

The size and mass of a new star is determined by the amount of material available in the molecular cloud. More material means a larger and more massive star, while less material results in a smaller and less massive star.

5. Can new stars form anywhere in the universe?

New stars can form in any region of the universe that contains a sufficient amount of gas and dust. However, the rate of star formation is higher in areas with high concentrations of gas and dust, such as in galaxies and nebulae.

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