A massive star with a mass of approximately 15 solar masses will eventually become a red supergiant.
Describe and explain the next stages of evolution of this massive star.
Sirius A is a bright star in the constellation Canis Major. The table below shows some data about Sirius A and about our Sun.
| Sirius A | Sun | |
|---|---|---|
| Surface temperature / K | 5.8×1035.8 \times 10^35.8×103 | |
| Luminosity / W | 9.77×10279.77 \times 10^{27}9.77×1027 | 3.85×10263.85 \times 10^{26}3.85×1026 |
| Wavelength of emitted light at peak intensity / nm | 290290290 | 500500500 |
Show that the surface temperature of Sirius A is approximately 10 000 K10\,000\text{ K}10000 K.
Calculate the radius of Sirius A.
An astronomer claims to have discovered a stable white dwarf star with a mass equal to 1.81.81.8 times that of our Sun.
Suggest why this claim must be incorrect.
