Stellar Evolution
4 marks · EasyA student observes two stars in the night sky: Star X is a red star, and Star Y is a blue star. Both are located in the same galaxy.
State which star has the higher surface temperature. Explain your answer.
Stars go through several stages in their life cycle. Name two stages a star like our Sun will go through after its main sequence period.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) Star Y (blue) has the higher surface temperature because blue stars are hotter than red stars. · must show Identifies blue star as hotter, Explanation based on star colour/temperature link
(b) After the main sequence, a star like the Sun becomes a red giant, then a white dwarf (and later a black dwarf). · must show Red giant stage, White dwarf stage, Accept black dwarf if both others are correct
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States Star Y (blue) is hotter.
B2 (a) · 1 mark · Explains that blue stars are hotter than red stars.
B3 (b) · 1 mark · Names red giant stage after main sequence.
B4 (b) · 1 mark · Names white dwarf stage (accept black dwarf).
Worked solution
a) Star Y (blue) has higher surface temperature because blue stars are hotter than red stars.
b) After the main sequence, a star like our Sun becomes a red giant, then a white dwarf.