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For over two decades, astronomers have observed an object called X7 located near the supermassive black hole at the center of the Milky Way galaxy. X7’s elongated shape has puzzled scientists, who have long debated its origin and characteristics. Was it formed by stellar winds or particles emitted by the black hole? Was it pulled off from a nearby structure? Using 20 years of data from the Galactic Center Orbit Initiative, researchers from the UCLA Galactic Center Group and the Keck Observatory have now developed a new theory about X7’s composition and its ultimate fate.
X7’s Composition and Evolution
According to the study published in The Astrophysical Journal, X7 could be a cloud of dust and gas ejected during the collision of two stars. X7 has a mass of approximately 50 Earths and is on an orbital path around the black hole, Sagittarius A* (Sgr A*), that would take about 170 years to complete. Over time, the black hole’s tidal force has stretched X7 and pulled it apart. X7’s shape has changed dramatically over the years, becoming more elongated as it moves closer to Sgr A*. Based on its trajectory, the research team estimates that X7 will make its closest approach to Sgr A* in 2036 and likely spiral toward it, eventually disintegrating.
The Role of Tidal Forces
As X7 approaches Sgr A*, it experiences tidal forces, which cause gravitational stretching. The side of the object closest to the black hole is pulled more strongly than the opposite end, leading to a change in X7’s shape and velocity. As it accelerates towards the black hole, X7 is gaining rapid momentum and has the potential to achieve remarkable speeds of up to 700 miles per second.
X7 Compared to G Objects
X7 exhibits some of the same characteristics as the so-called G objects that orbit Sgr A*. These objects look like gas but behave like stars. However, X7’s shape and velocity have changed more dramatically than those of the G objects. The research team believes that X7’s origin could also be related to the collision of two stars. When two stars merge, the new star is hidden inside a shell of dust and gas. The ejected gas from the merged star could produce objects like X7.
Implications of the Findings
The research team’s findings are the first estimate of X7’s mildly elliptical orbit and the most comprehensive analysis of its appearance, shape, and behavior to date. The findings suggest that X7 arose from the collision of two stars, which is a common phenomenon, particularly near black holes. The research team will continue to monitor X7’s changes as the black hole’s gravity exerts its force on it.
Studying the extreme environment at the center of the Milky Way requires the use of powerful tools, such as the Keck Observatory, located in Maunakea, Hawaii. The research team’s discovery highlights the privilege of studying the universe’s mysteries and opens up new avenues for exploration. While X7’s ultimate fate may be disintegration, the knowledge gained from studying it could lead to breakthroughs in our understanding of the universe and its workings.