Sagittarius A*
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Sagittarius A* (pronounced "A-star", standard abbreviation Sgr A*) is a bright and very compact source of radio emission at the center of the Milky Way Galaxy, part of a larger astronomical feature at that location (Sagittarius A). On October 16, 2002, the Max Planck Institute for Extraterrestrial Physics (MPE) reported visual confirmation of this as the supermassive black hole at the center of our galaxy. Later observations determined the mass of the object to be about 3.7 million solar masses (our sun's mass is approximately 2×1030 kg).
Sagittarius A* is "associated" with the supermassive black hole; what is seen is not strictly the black hole itself. The observed radio and infrared energy emanates from gas and dust heated to millions of degrees while falling into the black hole. The black hole itself emits no light. In the near future, astronomical interferometers may allow the direct imaging of the event horizon.
Coordinates (J2000): RA 17h 45m 40.045s Dec. −29.00775 degrees (About 10 degrees to the west of the center of the constellation Sagittarius, towards Scorpius)
[edit] External links
- UCLA Faculty Research presentation on Sagittarius A* (Video)
- 2004 paper deducing mass of central black hole from orbits of 7 stars (arxiv preprint)
- ESO video clip of orbiting star (533 KB MPEG Video)
- Star Orbiting Massive Milky Way Centre Approaches to within 17 Light-Hours ESO Press Release, October 16 2002
- The Galactic Center (outdated)
- Data and scientific papers about Sagittarius A*de:Sagittarius A*
