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Jul 8, 2021 · 0. The Universe is expanding and they say it will eventually become cold, and new star formation will stop. But galaxies are only moving away from each other, and each galaxy itself stays intact and the star formation etc activities happens inside galaxies. So why would expansion of universe affect this when galaxies themselves are not ...
- Universe Expansion
As the bread expands while baking, the actual universe is...
- Galaxies
For questions about the structure, composition, dynamics,...
- Universe Expansion
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. The length of time that they spend on the main sequence depends upon how quickly the hydrogen gets used up.
Models. A stellar evolutionary model is a mathematical model that can be used to compute the evolutionary phases of a star from its formation until it becomes a remnant. The mass and chemical composition of the star are used as the inputs, and the luminosity and surface temperature are the only constraints.
Small, relatively cold, low-mass red dwarfs fuse hydrogen slowly and will remain on the main sequence for hundreds of billions of years or longer, whereas massive, hot supergiants will leave the main sequence after just a few million years. A mid-sized star like the Sun will remain on the main sequence for about 10 billion years.
A similar thing happens in a star-forming nebula. As the cloud contracts in size due to gravity, it spins faster. Credit: Shutterstock.com. The process to form gas giant planets is thought only to occur in the outer part of the pre-stellar disk where temperatures are cold and the amount of gas available is high.
Apr 11, 2022 · Figure \(\PageIndex{1}\) Star Layers during and after the Main Sequence. (a) During the main sequence, a star has a core where fusion takes place and a much larger envelope that is too cold for fusion. (b) When the hydrogen in the core is exhausted (made of helium, not hydrogen), the core is compressed by gravity and heats up.
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Why do large stars burn faster than small stars?
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What happens when a star's luminosity and temperature change?
Stellar Structure and Evolution. Stars are the source of almost all of the light our eyes see in the sky. Nuclear fusion is what makes a star what it is: the creation of new atomic nuclei within the star’s core. Many of stars’ properties — how long they live, what color they appear, how they die — are largely determined by how massive ...
