in the constellation Ursa Major
7 million times the mass of the Sun
Diameter roughly 30 million miles (45 million km), about 30 times the diameter of the Sun.
An ultraviolet view of M81 from Europe's orbiting XMM-Newton X-ray telescope. The bright dot in the center represents the hot accretion disk that encircles the central black hole. [Alice Breeveld, University College, London]
This document was last modified: October 24, 2005.