Researchers Discover New Class of Objects Orbiting Sagittarius A
A group of researchers from UCLA Galactic Center Orbits Initiative has discovered a new class of objects that are orbiting Sagittarius A. According to the researchers, the objects look like gas and behave like stars.
Andrea Ghez and her group started their study after Ghez’s research group identified an unusual object at the center of our galaxy back in 2005. The object was later named G1 and in 2012, astronomers in Germany made a puzzling discovery of a bizarre object named G2. While it’s unclear, the research team believes that G2 is probably two stars that were orbiting the black hole before merging to form an extremely large star.
Ghez said, “At the time of closest approach, G2 had a really strange signature. We had seen it before, but it didn’t look too peculiar until it got close to the black hole and became elongated, and much of its gas was torn apart. It went from being a pretty innocuous object when it was far from the black hole to one that was really stretched out and distorted at its closest approach and lost its outer shell, and now it’s getting more compact again.”
Mark Morris, UCLA professor of physics and astronomy added, “One of the things that has gotten everyone excited about the G objects is that the stuff that gets pulled off of them by tidal forces as they sweep by the central black hole must inevitably fall into the black hole. When that happens, it might be able to produce an impressive fireworks show since the material eaten by the black hole will heat up and emit copious radiation before it disappears across the event horizon.”
In order to find out more, the team continued the research to discover four more objects called: G3, G4, G5 and G6. According to the researchers, although G1 and G2 have similar orbits, the four new objects have different orbits. Although not certain, Ghez believes that all of the six objects were most likely binary stars that merged due to the strong gravitational pull.
Ghez added, “Mergers of stars may be happening in the universe more often than we thought, and likely are quite common. Black holes may be driving binary stars to merge. It’s possible that many of the stars we’ve been watching and not understanding may be the end product of mergers that are calm now. We are learning how galaxies and black holes evolve. The way binary stars interact with each other and with the black hole is very different from how single stars interact with other single stars and with the black hole.”
At the moment, the researchers have identified more candidates that they believe might be part of the new class.