These Mysterious Objects Are Gathering Around The Supermassive Black Hole At The Center Of Our Galaxy

Thursday, 07 June 2018 - 12:45PM
Astronomy
Black Holes
Thursday, 07 June 2018 - 12:45PM
These Mysterious Objects Are Gathering Around The Supermassive Black Hole At The Center Of Our Galaxy
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Image credit: NASA
Here's a riddle that's puzzled astronomers for years: what looks like a giant gas cloud, acts like a star, and orbits the supermassive black hole in the center of the Milky Way?

Whatever the answer is, new data pulled from the W. M. Keck Observatory has spotted three more of these strange cosmic bodies, called "G-objects." This new trio joins the original two spotted in 2004 and 2012, dubbed G-1 and G-2, and deepen the ongoing mystery of just what is going on at our Galactic Center.

What's strange about these G-objects – especially G-1 and G-2 – is that they look like big clouds of gas and dust orbiting our resident black hole, but don't get pulled apart when they get close. Instead, they keep themselves together and keep orbiting, which makes astronomers think that they're actually big, bloated stars hidden under layers of gas.

If this is the case, that would make G-objects even weirder: the stars would have to be much, much bigger than normal ones. According to UCLA Astronomy Professor Mark Morris: "If they were gas clouds, G1 and G2 would not have been able to stay intact. Our view of the G-objects is that they are bloated stars–stars that have become so large that the tidal forces exerted by the central black hole can pull matter off of their stellar atmospheres when the stars get close enough but have a stellar core with enough mass to remain intact. The question is then, why are they so large?"



The leading theory is that each of these mega-stars is the result of a merger of a binary star system that crashed together while orbiting the black hole. If that's the case, then the G-objects are very special indeed: according to Andrea Ghez, who runs the Galactic Center Orbits Initiative, "If these objects are indeed binary star systems that have been driven to merge through their interaction with the central supermassive black hole, this may provide us with insight into a process which may be responsible for the recently discovered stellar mass black hole mergers that have been detected through gravitational waves."

To be clear, Ghez is talking about the pair of neutron stars that crashed into one another and provided us with the first evidence of gravitational waves. Interestingly enough, that collision didn't create a G-object... Instead, it may have created a tiny black hole.

In any case, the discovery of three more potential G-objects at the center of our galaxy (creatively named G-3, G-4, and G-5) means that astronomers will have more chances to study the incredibly powerful phenomenon of star mergers, though it will take at least 20 years to see if G-3 survives its first encounter with the black hole. In the meantime, hopefully studying G-1 and G-2 will be able to tell us more about the strange ecosystem at the heart of our galaxy.
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