The table below shows radiation data from two red giant stars measured by a space telescope. Fig. 1 represents the same stars as circles, drawn to scale onl...
Question 1 Report
The table below shows radiation data from two red giant stars measured by a space telescope. Fig. 1 represents the same stars as circles, drawn to scale only for relative size.
| star | surface temperature / K | radius / Sun radii | luminosity / Sun = 1 |
|---|---|---|---|
| J | 3400 | 90 | 1000 |
| K | 4200 | 35 | 350 |
(a) What is the surface temperature of K? [1]
(b) Describe two differences between J and K. [3]
(c) Explain why J has a greater luminosity than K. [4]
(d) Give two observations that would support the classification of J as a red giant. [2]
(e) Name the likely remnant of J if it began with a mass similar to the Sun. [2]
Answer Details
(a) K has a surface temperature of \(4200\text{ K}\). [1]
(b) J is cooler than K, \(3400\text{ K}\) compared with \(4200\text{ K}\). J has a larger radius, \(90\) rather than \(35\) Sun radii, and a greater luminosity, \(1000\) rather than \(350\) times the Sun's. [3]
(c) J has a much larger radius, so it has a much larger surface area. Radiation is emitted from this larger area, making its total energy radiated each second, its luminosity, greater than K's. [4]
(d) Supporting observations are its cool, red surface temperature and its very large radius or high luminosity. [2]
(e) If J began with a mass similar to the Sun, it will form a planetary nebula and leave a white dwarf remnant. [2]
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