1. 1
   An astronomy teacher explains to a class how stars form from large interstellar clouds of gas and dust that collapse under their own gravitational attraction, gradually heating up as the collapse continues.

   (a)

   An astronomy teacher explains that stars form from large clouds of gas and dust in space, which begin to collapse under gravity. What is the name given to a collapsing cloud of gas that has not yet become a stable star?

   [1 mark]

   • AA protostar
   • BA white dwarf
   • CA neutron star
   • DA black hole

   (b)

   As the collapsing cloud continues to contract, what happens to its temperature?

   [1 mark]

   • AIts temperature falls to absolute zero
   • BIts temperature decreases
   • CIts temperature stays exactly the same
   • DIts temperature increases

   (c)

   State the condition that must be reached for a protostar to become a stable star, in terms of the balance of forces acting on it.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   An astronomer is studying a star of similar mass to the Sun that has run out of hydrogen fuel in its core, expanded dramatically, and cooled, changing its appearance and colour.

   (a)

   An astronomer is studying a star that has run out of hydrogen fuel in its core and has begun to expand dramatically, becoming much cooler and redder in appearance. If this is a star of similar mass to the Sun, what is this expanded stage of the star's life called?

   [1 mark]

   • AA protostar
   • BA red giant
   • CA neutron star
   • DA supernova

   (b)

   The astronomer explains that this expanding star will eventually shed its outer layers, forming a cloud of gas around a small, extremely dense remnant at its centre. What is the name of this small, dense remnant?

   [1 mark]

   • AA black hole
   • BA red supergiant
   • CA white dwarf
   • DAn accretion disc

   (c)

   State the name given to the cloud of gas that surrounds the small, dense remnant formed when a star like the Sun sheds its outer layers, and state what eventually happens to that small, dense remnant over a very long period of time.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A different research team is studying a star far more massive than the Sun that has expanded into a red supergiant after using up the hydrogen fuel in its core, and is monitoring it for signs of an imminent supernova.

   (a)

   Describe what happens to this red supergiant when it eventually runs out of fuel for nuclear fusion, including the name of the violent event that occurs and what is produced as a result.

   [3 marks]

   (b)

   The team also explains that material from the nebula produced by a supernova can eventually form new stars, sometimes with orbiting planets. Explain how the heavier elements produced by a supernova could end up as part of a newly forming planet, and explain why this suggests that some of the atoms making up the Earth may have originally come from a star that exploded long before the Sun and Solar System formed.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A planetarium is designing a large timeline display showing the complete life cycle of stars, from formation through to their final remnants, covering both Sun-like stars and much more massive stars.

   (a)

   Describe, in order, the full life cycle of a star of similar mass to the Sun, from an interstellar cloud of gas and dust through to its final remnant, naming each stage and explaining briefly what happens at each stage.

   [6 marks]

   (b)

   The planetarium's display also needs to show how the life cycle differs for a star that is much more massive than the Sun. Describe, in order, the full life cycle of a much more massive star, from its formation through to its final remnant, naming each stage and explaining briefly what happens at each stage, and explain the two key differences between this life cycle and that of a star of similar mass to the Sun.

   [6 marks]

   Total for question 4: 12 marks

End of questions