The center of our galaxy is an exotic and fascinating place. The Milky Way Galactic Center is reigned by a supermassive black hole called Sagittarius A. Aside from possibly being surrounded by a swarm of 10,000 smaller black holes, as reported by the Inquisitr in April, Sagittarius A is also gravitated by mysterious celestial bodies known as “G-objects.”
The simplest way to describe these mystery objects dwelling at the center of our galaxy is as giant “puffballs.” A more elaborate description will tell you that they are enlarged bodies which look like puffy gas clouds but, for an inexplicable reason, actually behave more like stars.
This has driven astronomers to the conclusion that these baffling G-objects could be massive stars in disguise, cloaked by a veil of galactic dust.
The first G-object turned up on our telescopes’ “radars” in 2004; the second one was discovered more recently, in 2012, Phys.org reports. Both these objects were initially labeled as gas clouds, until something amazing happened. Dubbed G1 and G2, the two puffy objects passed very close to Sagittarius A and, against all odds, managed to survive its gravitational pull.
Had they truly been mere gas clouds, they would have been shredded apart by the black hole’s gravity, notes Mark Morris, an astronomy professor at the University of California, Los Angeles (UCLA) and a member of the university’s Galactic Center Orbits Initiative (GCOI).
At the American Astronomical Society Meeting that took place today in Denver, Colorado, Morris and his colleagues reported that three more G-objects have been spotted at the heart of the Milky Way, circling the supermassive black hole.
The three objects, which were given the imaginative names of G3, G4, and G5, were found after the UCLA team combed through 12 years’ worth of data from the W.M. Keck Observatory in Maunakea, Hawaii.
“These compact dusty stellar objects move extremely fast and close to our Galaxy’s supermassive black hole. It is fascinating to watch them move from year to year,” said research leader Anna Ciurlo, a UCLA postdoctoral scholar.
“How did they get there? And what will they become? They must have an interesting story to tell.”
According to the GCOI, the three G-objects — discovered with the help of Keck Observatory’s OH-Suppressing Infrared Imaging Spectrograph (OSIRIS) — may have formed from the merger of stars existing in binary systems, which were driven to crash into each other by Sagittarius A’s gravitational force.
“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,” says Morris.
This would explain why these objects are so distended and sport a “puffy” appearance. If this is the case, then it might take a while, possibly even a million years, for these mysterious galactic inhabitants to settle into a more recognizable form and start looking like regular stars, Morris points out.
Andrea Ghez, founder and director of GCOI, believes that the most interesting thing about G-objects is that they “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.”
What Ghez is referring to is the collision of neutron stars detected in 2017 — the first time our telescopes ever picked up gravitational waves. Earlier this month, this historic event was shown to have become the birthplace of a very unusual black hole, the Inquisitr reported at the time.
Finding three extra G-objects in the center of the Milky Way might help unravel the process in which binary stars, such as the aforementioned neutron stars, merge to form something completely new.
As the Inquisitr previously reported, the Laser Interferometer Space Antenna (LISA) observatory will be launched into space in 2014 with the goal of scouring the skies in search of binary pairs of celestial objects.
Meanwhile, astronomers will be keeping tabs on the newfound G-objects to see if they survive the close encounter with Sagittarius A, just like G1 and G2.
“We’ll have to wait a few decades for this to happen; about 20 years for G3, and decades longer for G4 and G5,” said Morris. “In the meantime, we can learn more about these puffballs by following their dynamical evolution using OSIRIS.”
Ciurlo explains why getting to the bottom of this peculiar matter is so important.
“Understanding G-objects can teach us a lot about the Galactic Center’s fascinating and still mysterious environment. There are so many things going on that every localized process can help explain how this extreme, exotic environment works.”