Sagittarius A* | Monsters of the Milky Way | How the Universe Works
Monsters of the Milky Way | How the Universe Works
Why is Sagittarius A* Important?
The stars orbiting close to Sagittarius A* are called “S stars.” Their close orbits and high velocities help astronomers determine the limits to the physical size of the Milky Way's central black hole.
How much mass does Sagittarius A* have?
From examining the Keplerian orbit of S2, they determined the mass of Sagittarius A* to be 4.1±0.6 million solar masses, confined in a volume with a radius no more than 17 light-hours (120 AU [18 billion km; 11 billion mi]).