Illustration comparing the size of four small stars. The largest of the four is Sirus A, a blue-white star roughly 1.7 times the size of the Sun. The yellow one is the Sun, a main sequence dwarf with a diameter of 1.39 million km (865, 000 miles). The red star is Proxima Centauri, a red dwarf and of the closest star to the Sun. At 200, 000 km (125, 000) across it is only 1/7 the size of the Sun, not much larger than the planet Jupiter. Lastly, the small white star is Sirius B, a white dwarf. It is only 8 per cent of the size of the Sun, smaller even than the planet Earth.