G2 is a mysterious object in the heart of our Milky Way galaxy. It has been postulated that G2 is an immense cloud of hydrogen gas on course to be devoured by Sagittarius A*, the supermassive black hole at the Milky Way’s center. However, rather than being ripped to shreds by the intense gravity of the black hole, instead G2 has continued in its orbit.
“We are seeing phenomena about black holes that you can’t watch anywhere else in the universe,” Ghez said. “We are starting to understand the physics of black holes in a way that has never been possible before.”
Now, new research by a team led by Andrea Ghez of the University of California, Los Angeles has ascertained the true, strange nature of G2. According to a UCLA statement, Ghez and team found that G2 is actually a pair of binary stars that had been orbiting Sagittarius A* together. Now they have merged to form an extremely massive star surrounded by gas and dust.
Ghez and colleagues used the optical and infrared telescopes at the W. M. Keck Observatory in Hawaii. The adaptive optics of those instruments offer a unique means of studying Sagittarius A*, as they mitigate the distortion effects of Earth’s atmosphere in real time.
G2 is one of a number of giant stars being created around the black hole as the overwhelming gravity fuses binary stars together. When such a merging occurs, the resultant giant star inflates for more than a million years. G2 is at the end of that process, and is now enduring what Ghez termed “spaghetti-fication”, becoming elongated as it circles the black hole. The surrounding cloud of dust and gas formed as nearby stars heated the surface of G2.
The new findings were published on November 3rd in the journal Astrophysical Journal Letters.
G2 Survives Supermassive Black Hole In The Milky Way Galaxy.