Astronomers from the UCLA Galactic Center Orbits Initiative have discovered a new class of objects that are orbiting the supermassive black hole at the center of our galaxy. That black hole is called Sagittarius A, and the team says that the bizarre objects look like gas and behave like stars.
The team notes that the objects look compact most of the time and then stretch out when their orbits bring them closest to the black hole. The orbits range from about 100 to 1,000 years. The first of the strange objects were discovered in 2005 and was dubbed G1. In 2012, astronomers found another object called G2 in the center of the Milky Way that made its closest approach to the black hole in 2014.
G2 is said to most likely be two stars that had been orbiting the back hole in tandem and merged into an extremely large star that is cloaked in unusually thick gas and dust. At the end of its closest approach, G2 had a “really strange signature,” according to one researcher. As it neared the black hole, the object lost its outer shell, and as it left the black hole, it stretched out and became distorted again.
To figure out of G1 and G2 were outliers, the scientists continued their investigation and found four more objects called G3, G4, G5, and G6. The four new objects have very different orbits than G1 and G2. The scientists believe that all six objects were binary stars that merged because of the strong gravitational forces of the black hole.
The merging of two stars takes more than a million years to complete. The team says that mergers of stars might be more common than previously believed, with black holes being the driving force for those mergers. The team has identified more candidates that may be part of the new class and is continuing its research.