Chandra Release - October 13, 2005

Visual Description: Sagittarius A*

Chandra's X-ray image of Sagittarius A* (left) has provided evidence for a new and unexpected way for stars to form. Sagittarius A*, the Milky Way's central black hole, is depicted in an illustration on the right. At the center of the illustration, there is a dark dot surrounded by a bright, circular object that resembles a doughnut. This ring-shaped structure, known as an accretion disk, is composed of gas and dust particles that orbit around the black hole due to its immense gravitational pull. The color of the accretion disk is predominantly red and orange with bright yellow towards the center. According to the standard model for star formation, gas clouds from which stars form should have been ripped apart by tidal forces from the supermassive black hole. Evidently, the gravity of a dense disk of gas around Sagittarius A* offsets the tidal forces and allows stars to form. The tug-of-war between the black hole's tidal forces and the gravity of the disk has also favored the formation of a much higher proportion of massive stars than normal.