14 DAY TRIAL // Some time ago, astronomers documented the presence of a fairly odd celestial body at the center of our home galaxy. For quite a while, this object, dubbed G2, was said to be no more and no less than a cloud of hydrogen gas traveling towards the massive black hole at the core of the Milky Way.
However, a paper published in the journal Astrophysical Journal Letters this past November 3 argues that there is more to this bizarre celestial body than meets the eye.
In a nutshell, astronomers with the University of California – Los Angeles in the US claim that, having analyzed data provided by optical and infrared telescopes in Hawaii, they identified this object as a massive star surrounded by dust and gas.
Turning stars into puppets on a string
In their paper in the Astrophysical Journal Letters, the University of California – Los Angeles scientists explain that, as shown by previous investigations, black holes have such a strong gravitational pull that not even light can escape them.
Hence, it does not really make sense for the strange object found at the center of the Milky Way to be simply a gas cloud. As the astronomers explain, were this object to be no more and no less than a mass of gas, the black hole in its proximity would have surely ripped it apart by now.
Thus, G2 remained unaffected even when it made its closest approach to the black hole this past summer. “G2 survived and continued happily on its orbit. A simple gas cloud would not have done that,” said researcher Andrea Ghez.
“G2 was basically unaffected by the black hole. There were no fireworks,” the University of California – Los Angeles astronomer went on to explain. Consequently, Andrea Ghez and fellow researchers believe that G2 is a massive star birthed by two smaller ones.
More precisely, the scientists say that this humongous star came into being when two slightly smaller ones that once formed a binary system came together and merged. The merger is argued to have occurred under the influence of gravitational pull the black hole.
Otherwise put, evidence at hand indicates that G2 is a massive star that formed after the black hole at the center of the Milky Way turned two stars in a binary system into its marionettes and got them to crash into each other and form a new one.
Not your usual massive star
Andrea Ghez and colleagues say that, having taken their time studying G2, they found its anatomy to be somewhat bizarre. Specifically, they claim that the black hole is still acting on this celestial body, causing it to become elongated. The astronomers jokingly refer to this process as spaghettification.
Besides, University of California – Los Angeles astronomers argue that G2's body is now hidden from view because nearby stars have heated its surface to such an extent that a massive cloud of dust and gas has come to form all around it.
Interestingly enough, it is said that G2 almost surely isn't the only celestial body of its kind. On the contrary, chances are that the black hole at the center of our home galaxy has until now formed several such stars and will continue to birth new ones in the millennia to come.
As Andrea Ghez put it, “This may be happening more than we thought. 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.”