Astronomers discover 1st binary star system orbiting Milky Way’s central supermassive black hole
The stars orbiting Sag A*. Click for original image.
Using infrared spectroscopic data gathered from 2005 to 2019 by the Very Large Telescope in Chile, astronomers have identified the first known binary star system to orbit Sagittarius A* (pronounced “A-star”), the Milky Way’s central supermassive black hole.
You can read their science paper here [pdf]. The white dot at the center of the map to the right marks the location of Sagittarius A*, while the red dot marks the present location of the binary star, dubbed D9. The other objects are the stars previously identified orbiting the central black hole, all of which are now believed to be single stars. The binary D9 has an estimated orbit around Sagittarius A* of 432 years and is thought to be less than three million years old. The two stars have approximate masses of 3.86 and 2.8 solar masses, with the smaller orbiting the larger every 372 days.
There is a lot of uncertainty in these numbers, but the data identifying the binary is quite firm. This discovery, as well as the many other stars now known to orbit Sagittarius A*, show that star formation so close to a supermassive black hole is not only possible, it is common, something astronomers a decade ago thought impossible.
The stars orbiting Sag A*. Click for original image.
Using infrared spectroscopic data gathered from 2005 to 2019 by the Very Large Telescope in Chile, astronomers have identified the first known binary star system to orbit Sagittarius A* (pronounced “A-star”), the Milky Way’s central supermassive black hole.
You can read their science paper here [pdf]. The white dot at the center of the map to the right marks the location of Sagittarius A*, while the red dot marks the present location of the binary star, dubbed D9. The other objects are the stars previously identified orbiting the central black hole, all of which are now believed to be single stars. The binary D9 has an estimated orbit around Sagittarius A* of 432 years and is thought to be less than three million years old. The two stars have approximate masses of 3.86 and 2.8 solar masses, with the smaller orbiting the larger every 372 days.
There is a lot of uncertainty in these numbers, but the data identifying the binary is quite firm. This discovery, as well as the many other stars now known to orbit Sagittarius A*, show that star formation so close to a supermassive black hole is not only possible, it is common, something astronomers a decade ago thought impossible.
