7.1 The Solar System & Lifecycles of Stars

Figure 1 shows the 5 stages of the life cycle of a star that has a similar mass to the Sun. 

Figure 1  

State and explain what happens in stage 2 of Figure 1. 

Include details of the forces involved and what they depend on.

State and explain what happens in stage 4 of Figure 1.

The average length of time a star stays in stage 3 is 10⁹ to 10¹¹ years. 

Explain why the star remains stable during stage 3 for this length of time.

For stars with much larger masses than our Sun, stages 1 to 3 in Figure 1 are almost exactly the same as lower-mass stars. The processes begin to differ for the later stages, 4 and 5.

Compare and contrast the final two stages in stars with much larger masses than our Sun and stars with similar masses to our Sun.

Figure 1 contains information on the mass of different stars.

Figure 1  

Compare the masses of Proxima Centauri and VY Canis Majoris to the Sun.

Explain how these differences will affect the time these stars can remain stable.

Describe what will happen to each of the stars after they leave the main sequence stage.

The Asteroid Belt is part of our Solar System.

Vesta is an asteroid in the Asteroid Belt.

Vesta orbits the Sun between the orbits of

Vesta has an orbital speed of 1.9 × 10⁴ m/s.

Vesta travels a distance of 2.2 × 10¹² m when it orbits the Sun once.

Calculate the time taken for Vesta to orbit the Sun once.

time = ............................................................. s

Higher Only

Explain why Vesta is accelerating even when it is travelling at a constant speed.

Higher Only

Energy is transferred from the Sun to Vesta by radiation.

Explain why the temperature on Vesta does not continue to rise, even though it is absorbing energy from the Sun.

The distance between Vesta and the Sun is 2.4 AU.

1AU is the distance between the Earth and the Sun.

The intensity of the Sun’s radiation reaching the Earth is 1400 W/m².

1W = 1 J/s
The intensity of the Sun’s radiation at a distance, d, from the Sun is given by the equation

where K always has the same value.

[1]

[3]

intensity = ............................................................. W/m²

Describe how stars are formed.

Explain why the star remains stable during the main sequence phase.

The life cycle of a star following the main sequence period depends on the size of the star.  A particular star is much larger in size than the Sun. 

Complete the stages of the life cycle of this star.

Describe what happens in the red giant phase.

Rearrange the stages of the life cycle of a star into the correct order.

A star can be in its main sequence phase for billions of years.

Figure 1 shows the forces acting on the Sun during this stable stage of its life cycle. 

Figure 1

Explain which star could eventually become a neutron star.

For stars with much larger masses than our Sun, the first 4 stages are almost exactly the same as for lower mass stars. For the later stages the processes begin to differ.

Compare and contrast the final two stages in stars with much larger masses than our Sun and stars with similar masses to our Sun.

Describe the evolution of a main sequence star to the point at which it becomes a black hole. 

State and explain whether the Sun will eventually become a black hole. 

An identical 10 kg object is sent to each planet.

Describe the differences between the heliocentric and geocentric models of the solar system.