Astronomers Discover What the Bizarre Object at the Center of the Milky Way Really Is
Astronomers may have found out exactly what a certain thin, bizarre object at the center of our galaxy might be. They've discovered that this object isn't a hydrogen gas cloud, but may instead be a pair of binary stars that is orbiting the black hole at the center of the Milky Way galaxy.
The object itself is widely known as G2. In the past, astronomers believed that it was a hydrogen cloud; however, if it had been one, it could have been torn apart by the black hole at the center of our galaxy, and the resulting celestial fireworks would have dramatically changed the state of the black hole.
"G2 survived and continued happily on its orbit; a simple gas cloud would not have done that," said Andrea Ghez, one of the researchers, in a news release. "G2 was basically unaffected by the black hole. There were no fireworks."
So what is G2? The astronomers believe that it's just one of an emerging class of stars near the black hole that are created because the black hole's powerful gravity drives binary stars to merge into one. In our galaxy, massive stars usually come in pairs. It's likely that the star in this case suffered an abrasion to its outer layer, but will otherwise be fine. When two stars near the black hole merge into one, the star expands for more than one million years before it settles back down. It seems that G2 is in this inflated stage.
"This may be happening more than we thought," said Ghez. "The stars at the center of the galaxy are massive and mostly binaries. 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."
Currently, G2 is becoming elongated near the black hole. At the same time, G2's surface is being heated by stars around it, creating an enormous cloud of gas and dust that has shrouded most of the massive star.
The findings are published in The Astrophysical Journal.