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| courses:phy100:7 [2023/08/05 11:35] – asad | courses:phy100:7 [2023/11/25 23:08] (current) – [3.2 High-mass stars] asad | ||
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| We are born to die. Life is nothing but a bridge between the stations of birth and death. Same is true for stars. What happens to a star as it goes from birth to death through the bridge of life? | We are born to die. Life is nothing but a bridge between the stations of birth and death. Same is true for stars. What happens to a star as it goes from birth to death through the bridge of life? | ||
| - | {{https:// | + | {{:courses: |
| It depends on the mass of the star as shown above. Key events in the life of a low-mass and medium mass star (A, F, G, K and M-types) are shown above, and key events in the life of a high-mass star (O and B-types) are shown below. | It depends on the mass of the star as shown above. Key events in the life of a low-mass and medium mass star (A, F, G, K and M-types) are shown above, and key events in the life of a high-mass star (O and B-types) are shown below. | ||
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| Let us say a low and a high mass star has formed from a nebula already. The stars are now in a stable state, so they are called **main sequence star**. What happens as next are described below for the two different stars. | Let us say a low and a high mass star has formed from a nebula already. The stars are now in a stable state, so they are called **main sequence star**. What happens as next are described below for the two different stars. | ||
| - | ==== - Low-mass | + | ==== - Lightweight |
| Always keep in mind that the inward pull of gravity (G) must equal the combined outward push of hot gas (P) and nuclear explosion (N) in order to keep the star stable, in the main sequence. But after living for around 10 billion years a low-mass star like the sun will run out of fuel for nuclear reaction. What is this fuel? | Always keep in mind that the inward pull of gravity (G) must equal the combined outward push of hot gas (P) and nuclear explosion (N) in order to keep the star stable, in the main sequence. But after living for around 10 billion years a low-mass star like the sun will run out of fuel for nuclear reaction. What is this fuel? | ||
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| After a while, the planetary nebula will disperse into space, go away and only the tiny core will remain. When the envelope was expanding into a nebula, the core was contracting. As it contracts, it heats up even more and becomes white-hot. At that point it is called a **white dwarf**. This is the final fate of a poor star like our sun. | After a while, the planetary nebula will disperse into space, go away and only the tiny core will remain. When the envelope was expanding into a nebula, the core was contracting. As it contracts, it heats up even more and becomes white-hot. At that point it is called a **white dwarf**. This is the final fate of a poor star like our sun. | ||
| - | ==== - High-mass | + | ==== - Heavyweight |
| But if a star is more massive, the fate will be different as you see in the lower panels of the diagram above. | But if a star is more massive, the fate will be different as you see in the lower panels of the diagram above. | ||
courses/phy100/7.1691256957.txt.gz · Last modified: 2023/08/05 11:35 by asad