Sirius B compared to the Earth, illustration. Sirius B (left) is a white dwarf star, an extremely hot, dense star formed from the collapsed core of a large star. It lies around 8.6 light years from Earth (right), and is the companion star to Sirius, the brightest star in the sky. Although it is hot it is faint due to its size, and is invisible with the naked eye. It is around 12, 000 kilometres across, just smaller than the Earth, but much denser with a mass that is 98 percent of that of our Sun. Sirius B's powerful gravitational field is 350, 000 times greater than Earth's. |