It is also one of the largest and most luminous observable stars. It has a radius between 950 to 1,000 times wider than the Sun. This means it is 1.322 to 1.392 billion kilometers in diameter. Betelgeuse was the first star other than the Sun whose size was known. The star's distance from Earth is about 640 light-years. Its average absolute magnitude is about −6.02. 