Sagittarius A* (pronounced "Sagittarius A-star", standard abbreviation Sgr A*) is a bright and very compact astronomical radio source at the center of the Milky Way, near the border of the constellations Sagittarius and Scorpius. It is part of a larger astronomical feature known as Sagittarius A. Sagittarius A* is the location of a supermassive black hole, like those that are now generally accepted to be at the centers of most if not all spiral and elliptical galaxies. Observations of a number of stars, most notably the star S2, orbiting around Sagittarius A* have been used to show the presence of, and produce data about, the Milky Way's central supermassive black hole, and have led to the conclusion that Sagittarius A* is the site of that black hole.
Distance: 25635 to 457 to 130 ly
Mass: 4.3 million times the sun mass