<Tr> <Th_colspan="2"> Database references </Th> </Tr> <Tr> <Td> SIMBAD </Td> <Td> data </Td> </Tr> <P> 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 thought to be the location of a supermassive black hole, like those that are now generally accepted to be at the centers of most spiral and elliptical galaxies . Observations of the star S2 in orbit 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 . </P> <P> Astronomers have been unable to observe Sgr A * in the optical spectrum because of the effect of 25 magnitudes of extinction by dust and gas between the source and Earth . Several teams of researchers have attempted to image Sagittarius A * in the radio spectrum using very - long - baseline interferometry (VLBI). The current highest - resolution measurement, made at a wavelength of 1.3 mm, indicated an angular diameter for the source of 37 μas . At a distance of 26,000 light - years, this yields a diameter of 44 million kilometers . For comparison, Earth is 150 million kilometers from the Sun, and Mercury is 46 million kilometers from the Sun at perihelion . The proper motion of Sgr A * is approximately − 2.70 mas per year for the right ascension and − 5.6 mas per year for the declination . </P>

What is the name of the black hole in the milky way