Answer:
It is due to the temperature of the star.
Explanation:
The colour of star depends on the temperature of star.
Blue coloured star has high temperature rather than red coloured star.
As we know that blue coloured light ( low wavelength ) has high energy as compared to red light ( high wavelength ) has low energy.
Energy is inversely proportional to the wavelength of light.
So, the temperature of Alpha Centauri is such that it emits yellowish light.
