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What two forces are active in a star to achieve stellar equilibrium?
Pressure and gravity. Pressure due to fusion reactions pushes outwards. Gravity pulls inwards to keep the star in equilibrium.
Which forces are at equilibrium within any star?
For the majority of the life of a star, the gravitational force (due to the mass of the star) and the gas pressure (due to energy generation in the core of the star) balance, and the star is said to be in ‘hydrostatic equilibrium’.
What happens when a star reaches equilibrium?
In a stable star, the gas pressure pushing out from the center is equal with the gravity pulling atoms inward to the center – when these forces are equal, the star is at equilibrium. Once a star reaches equilibrium for the first time, it will start burning (fusing) hydrogen into helium.
When stars begin to run out of fuel they first become?
When a main sequence star begins to run out of hydrogen fuel, the star becomes a red giant or a red super giant. THE DEATH OF A LOW OR MEDIUM MASS STAR After a low or medium mass or star has become a red giant the outer parts grow bigger and drift into space, forming a cloud of gas called a planetary nebula.
What 2 forces are acting on a star?
Gravitational forces act to contract the star. Fusion reactions and heat convection act to expand the star. The two forces are balanced and the star remains stable in size and reactions.
What are 2 main forces that act on gases in a star?
While self-gravity pulls the star inward and tries to make it collapse, thermal pressure (heat created by fusion) pushes outward. These two forces cancel each other out in a main sequence star, thus making it stable.
What is the force pushing a star outward?
Gravity constantly works to try and cause the star to collapse. This pressure counteracts the force of gravity, putting the star into what is called hydrostatic equilibrium. A star is okay as long as the star has this equilibrium between gravity pulling the star inwards and pressure pushing the star outwards.
When a star is stable the forces pushing outwards are?
(b) Figure 2 shows the forces acting on a star when the star is stable. Draw a ring around the correct answer to complete the sentence. When a star is stable, the forces pushing outwards are bigger than smaller than balanced by the forces pulling inwards.
What Do All stars start as?
All stars start in a large cloud of dust and gas called a nebula. Gravity can pull some of the gas and dust in a nebula together, forming a proto-star.
What is the earliest stage of a star?
protostar
A protostar is the earliest stage of a star’s life. A star is born when the gas and dust from a nebula become so hot that nuclear fusion starts.
What is the outward force in a main sequence star?
In the Main Sequence Phase of a star’s evolution, radiation pressure pushing outward exactly balances the gravitational pressure pulling inward (this balance is called Hydrostatic Equilibrium). Because these two forces are exactly in balance, the star is stable (this means it neither shrinks nor expands).
What does it mean for a star to be at equilibrium?
The term equilibrium does not mean that there isn’t any change in the star. It just means that there is not a net overall change in the star. In a stable star, the gas pressure pushing out from the center is equal with the gravity pulling atoms inward to the center – when these forces are equal, the star is at equilibrium.
Why does a star remain in a stable state after fusion?
The fusion reaction releases energy and it push the matter inside the star outwards and gravity pulls the matter inwards. These two forces are in equilibrium as the star evolves in the main sequence..So the star remains in a stable state.
How does gravity affect the stability of a star?
At every layer within a stable star, there is a balance between the inward pull of gravitation and the gas pressure. This is a stable equilibrium, for if gravity were greater than the gas pressure, the star would contract. On the other hand, if the gas pressure were greater, then the star would expand.
Why do stars have to have a stable inner core?
This, by extension, means that the temperature and density of a gas in that layer has to be higher as well. This means that for a star to be stable, a star’s inner core must have a high temperature, density, and pressure to support its own weight. This is easy to remember. Let’s think of another pyramid to illustrate why.