Question

1. in what stage do stars spend most of their lives?
2. what does the lifespan of a star depend on?
3. why do less massive stars have a longer lifespan than large massive stars?
4. after the main-sequence stage, what will massive stars become?
5. what do most average stars form when they collapse after the red giant stage?
6. what do most massive stars form when they reach the end of the red supergiant phase?
7. what will a massive star about 1.4 times the size of the sun end its life as?
8. where is every atom in our bodies created?
9. copy the life cycle of a star diagram in the space below.

task 6: life cycle of stars video
use any method to watch the life cycle of stars video by fuse school. answer the questions below as you watch.
full url: https://www.youtube.com/watch?v=bg-ukub_squ

1. what force causes the dust and gas inside a nebula to spiral together?
2. what has to occur for a star to form?
3. what factor determines what the star will become after the main-sequence stage?

Explanation:

These questions are about the life cycle of stars, which falls under the subfield of Physics (a part of Natural Science). To answer them, we can refer to the knowledge of stellar evolution:

• Q27: Stars spend most of their lives in the main - sequence stage. During this stage, hydrogen fusion occurs in the core, providing a stable energy source.
• Q28: The lifespan of a star depends on its mass. More massive stars consume their nuclear fuel faster.
• Q29: Less massive stars have a longer lifespan because they consume their nuclear fuel (hydrogen) at a slower rate. Their lower mass means the gravitational pressure in the core is less, so the fusion reactions proceed more slowly.
• Q30: After the main - sequence stage, massive stars will become red supergiants. They expand and cool, and their core starts fusing heavier elements.
• Q31: Most average stars (like our Sun) form a white dwarf when they collapse after the red giant stage. After the red giant phase, the outer layers are shed, and the core, which is mostly carbon and oxygen, collapses to form a white dwarf.
• Q32: Most massive stars form a supernova when they reach the end of the red supergiant phase. The core collapses rapidly, and then there is a violent explosion.
• Q33: A massive star about 1.4 times the size of the sun (Chandrasekhar limit) will end its life as a neutron star. If the mass is above this limit, it may become a black hole, but 1.4 solar masses leads to a neutron star formation after a supernova.
• Q34: Every atom in our bodies (except hydrogen) is created in stars. Stars fuse lighter elements to form heavier ones, and when they explode (supernovae), these elements are scattered into space and become part of new celestial bodies and eventually us.
• Q35: The Life Cycle of a Star diagram typically shows the stages: Nebula -> Protostar -> Main - Sequence Star -> (for average stars) Red Giant -> Planetary Nebula -> White Dwarf; (for massive stars) Red Supergiant -> Supernova -> Neutron Star or Black Hole.
• Q36: Gravity is the force that causes the dust and gas inside a nebula to spiral together. Gravity pulls the particles towards the center, starting the process of star formation.
• Q37: For a star to form, gravitational collapse of a nebula (a cloud of gas and dust) must occur. As the gas and dust come together, the temperature and pressure in the core increase until nuclear fusion (of hydrogen into helium) starts.
• Q38: The mass of the star determines what the star will become after the main - sequence stage. Massive stars have different evolutionary paths (red supergiant -> supernova -> neutron star/black hole) compared to average - mass stars (red giant -> planetary nebula -> white dwarf).

Answer:

1. Main - sequence stage
2. Its mass
3. Less massive stars consume fuel slower.
4. Red supergiants
5. White dwarf
6. Supernova
7. Neutron star
8. In stars
9. (Draw the diagram with stages: Nebula → Protostar → Main - Sequence Star → (Average: Red Giant → Planetary Nebula → White Dwarf; Massive: Red Supergiant → Supernova → Neutron Star/Black Hole))
10. Gravity
11. Gravitational collapse of nebula and start of nuclear fusion.
12. The mass of the star