For two decades, scientists have been studying X7, an elongated object near the supermassive black hole at the center of the Milky Way, in an effort to determine its origins. They have wondered if it was pulled off a larger structure nearby, if its shape was caused by stellar winds or if it was shaped by jets of particles from the black hole.
Now, astronomers from the UCLA Galactic Center Group and the Keck Observatory have proposed that X7 could be a cloud of dust and gas that was ejected during the collision of two stars. They studied the evolution of X7 using 20 years of data gathered by the Galactic Center Orbit Initiative and observed that over time, X7 has stretched and is being pulled apart as the black hole drags it closer, exerting its tidal force upon the cloud. The team expects that X7 will disintegrate within the next few decades, with the gas and dust eventually being drawn toward the black hole called Sagittarius A* (Sgr A*).
X7 has a mass of about 50 Earths and is on an orbital path around Sgr A* that would take 170 years to complete. However, the team estimates that X7 will make its closest approach to Sgr A* around the year 2036 and then likely spiral toward Sgr A* and disappear.
While X7’s origin is still debated, the findings suggest that it arose after two stars collided. One possibility is that X7’s gas and dust were ejected at the moment when two stars merged. The research team will continue to use the Keck Observatory to monitor X7’s changes as the power of the black hole’s gravity yanks it apart.
The findings are the first estimate of X7’s orbit and the most robust analysis to date of its changes in appearance, shape and behavior. The team observed that X7’s shape and velocity have changed more dramatically than those of other strange dusty objects orbiting Sgr A*. As it accelerates toward the black hole, X7 is moving rapidly at speeds of up to around 700 miles per second.
The study’s lead author, Anna Ciurlo, a UCLA assistant researcher, said,
“No other object in this region has shown such an extreme evolution. It started off comet-shaped and people thought maybe it got that shape from stellar winds or jets of particles from the black hole. But as we followed it for 20 years, we saw it becoming more elongated. Something must have put this cloud on its particular path with its particular orientation.”
Co-author Mark Morris, a UCLA professor of physics and astronomy, said,
“We anticipate the strong tidal forces exerted by the galactic black hole will ultimately tear X7 apart before it completes even one orbit.”
Image Credits
In-Article Image Credits
The first image of Sgr A*, the supermassive black hole at the center of our galaxy via Wikimedia Commons by EHT Collaboration with usage type - Creative Commons License. May 12, 2022Featured Image Credit
The first image of Sgr A*, the supermassive black hole at the center of our galaxy via Wikimedia Commons by EHT Collaboration with usage type - Creative Commons License. May 12, 2022
