Sagittarius A*

the supermassive black hole at the center of the Milky Way Galaxy

Sagittarius A* (Sgr A*) is a bright astronomical radio source at the center of the Milky Way. It is in the direction of the constellations Sagittarius and Scorpius.

Saggitarius A*
Saggitarius A* image by Chandra X-Ray Observatory
Observation data
TypeRadio source
Right ascension 17h 45m 40.05s
Declination±−29° 00′ 27.9″
Distance25900±1400 light years
Physical characteristics
Notable featuresRadio source in the center of the Milky Way
Other designationsSgr A*
See also: Diffuse nebula, Lists of nebulae

The radio source is part of a larger astronomical feature known as Sagittarius A. Sagittarius A* is thought to be a supermassive black hole,[1][2][3] like those that are at the centers of most spiral and elliptical galaxies. Observations of the star S2 in orbit around Sagittarius A* were used to show the presence of the Milky Way's central supermassive black hole. This led to the conclusion that Sagittarius A* is the site of that black hole.[4][5]



  1. Reynolds 2008
  2. Overbye, Dennis (8 June 2015). "Black Hole Hunters". NASA. Retrieved 8 June 2015.
  3. Overbye, Dennis; Corum, Jonathan; Drakeford, Jason (8 June 2015). "Video: Peering Into a Black Hole". New York Times. ISSN 0362-4331. Retrieved 9 June 2015.
  4. Henderson, Mark (December 9, 2008). "Astronomers confirm black hole at the heart of the Milky Way". Times Online. Retrieved 2009-05-17.
  5. Reynolds C. 2008. Astrophysics: bringing black holes into focus. Nature 455 (7209): 39–40. Bibcode:2008Natur.455...39R. doi:10.1038/455039a. PMID 18769426.

Other websites


  Media related to Sagittarius A* at Wikimedia Commons