A highly massive main-sequence star with a mass of approximately 25 solar masses will eventually evolve into a red supergiant.
Describe and explain the stages of evolution of this massive star after the red supergiant phase.
Regulus is the brightest star in the constellation Leo. The table below shows some stellar data comparing Regulus to our Sun.
| Regulus | Sun | |
|---|---|---|
| Surface temperature / K | 5.8×1035.8 \times 10^35.8×103 | |
| Luminosity / W | 1.35×10291.35 \times 10^{29}1.35×1029 | 3.85×10263.85 \times 10^{26}3.85×1026 |
| Wavelength of emitted light at peak intensity / nm | 240240240 | 500500500 |
Show that the surface temperature of Regulus is approximately 12 000 K12\,000\text{ K}12000 K.
Calculate the radius of Regulus.
An astronomer claims to have discovered a stable white dwarf star with a mass equal to 1.71.71.7 times that of our Sun.
Suggest why this claim must be incorrect.
