Classifying Stars
4 marks · NormalThe table below shows the classification and some properties of certain stars:
| Star | Class | Colour |
|---|---|---|
| Alpha | K | orange |
| Beta | B | blue-white |
| Gamma | M | red |
| Delta | G | yellow |
Which of the stars in the table above is likely to have the highest surface temperature? State your answer and explain your reasoning.
Which star class in the table is most similar to the Sun? Give the name and class.
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.
Show answer
(a) Beta (class B); B class stars are blue-white and are hotter than the other classes shown. · must show States Beta or class B, Explains reasoning using temperature vs class or colour
(b) Delta, class G · must show States Delta and G
Common mistakes: Incorrectly relating star colour to temperature order
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Identifies Beta (class B) as the hottest.
E1 (a) · 1 mark · Explains that class B stars are hotter than K, M, G or links colour blue-white to higher temperature.
M2 (b) · 1 mark · Identifies Delta as the star most similar to the Sun.
E2 (b) · 1 mark · States class G as the Sun’s classification.
Worked solution
(a) Beta is the class B star. Class B stars are blue-white and are among the hottest.
Therefore, Beta is likely to have the highest surface temperature because B is hotter than G, K, or M classes.
(b) The Sun is a class G star. In the table, Delta is the class G (yellow), so Delta is most similar to the Sun.