A groundbreaking discovery has unveiled a unique binary star, D9, orbiting closely around the supermassive black hole at the Milky Way’s core. Researchers from Germany and the Czech Republic found this binary system, composed of two stars with masses of 2.8 and 0.7 times that of the sun, amidst high-speed stellar activity. Despite its proximity to the black hole, which will eventually cause the stars to merge, this find offers new insights into star formation in extreme environments and the nature of nearby G-objects.
Binary stars may seem ordinary, but a groundbreaking discovery has revealed a unique binary star that orbits a black hole closely for the first time.
This exciting find is a combination of chance and keen observation: Researchers from Germany and the Czech Republic have identified a binary star situated near the supermassive black hole in the Milky Way’s core.
While star pairs are common—most stars exist in pairs or grouped systems—the celestial object known as D9 is distinctive. It is the only binary star recognized to orbit the supermassive black hole in such proximity, as highlighted in the journal Nature Communications. Florian Peißker from the University of Cologne, a key contributor to this discovery, states, ‘Black holes are not as destructive as we previously believed.’
Astronomers confirmed the existence of a black hole at the center of our galaxy, boasting a mass four million times that of our sun, back in the 1990s. Initially, it was thought that intense gravitational forces would prevent star formation near the black hole, but this assumption has been revised: Many stars are thriving within less than one light year of this monumental gravitational force.
The Struggle Against Gravity
Stars in this vicinity reach astonishing speeds of several thousand kilometers per second, allowing them to escape the black hole’s powerful gravitational grip. Given these extreme conditions, astronomers were initially surprised to find no binary stars in this area. However, the discovery of D9 has prompted a reevaluation of this perspective.
Peißker and his team stumbled upon the binary star unexpectedly while investigating G-objects—mysterious entities that orbit the black hole alongside the stars but appear as small clouds of gas and dust.
This revelation could lead to significant advancements in our understanding of black holes.
Deciphering 15 Years of Data
While examining these enigmatic celestial bodies, Peißker noticed unusual, consistent variations in the speed of star D9. ‘Initially, I thought I had made an error in my analysis,’ he recalls. Yet, the pattern persisted across 15 years of data, indicating that it was not a solitary star but rather a binary system influencing the observed speed changes.
The team’s research has identified two stars within this binary system, with masses of 2.8 and 0.7 times that of our sun, orbiting each other at a distance roughly one and a half times that of the Earth-Sun distance, with an orbital period of 372 days. This relatively close proximity grants the system stability; a larger distance would likely result in the gravitational pull of the black hole tearing the pair apart.
One of the stars, WOH G64, is part of the Large Magellanic Cloud star system, located 160,000 light-years away.
A Temporary Existence
Despite its remarkable discovery, D9 is not in a state of permanence. The proximity to the black hole disrupts its orbit, eventually leading to the two stars spiraling closer together and merging. This discovery is fortuitous, as the binary star is estimated to be 2.7 million years old and is expected to vanish in about a million years due to this merger. Emma Bordier from the University of Cologne notes, ‘Astronomically speaking, we have a limited opportunity to observe such a binary star, and we have achieved that!’
Although this find was accidental, it may also bring Peißker and Bordier’s team closer to their primary goal of understanding G-objects. Researchers suspect these may be remnants of binary stars that have yet to merge, alongside those that have already combined.
Future Investigations Ahead
A lingering question remains: how did these stars form in such close proximity to the massive black hole? With the advanced instruments at the European Southern Observatory (ESO) in Chile, scientists are optimistic about uncovering answers soon. Following the discovery of the binary star, Peißker even entertains the possibility of planets existing in this extreme environment, stating, ‘Detecting planets in the galactic center seems to be merely a matter of time.’
Source: dpa/fwt