Rare Star Explosion Reveals Black Hole In Milky Way Galaxy
Astronomers have discovered a rare X-ray star explosion close to the center of the Milky Way galaxy. The explosion revealed a previously unknown black hole siphoning gas away from a neighboring sun-like star.
NASA’s Swift satellite discovered the star explosion last month when it detected a new and rapidly brightening X-ray source just a few degrees away from the galactic center of the Milky Way, reports Yahoo! News.
Astronomers analyzed that the outburst was a short-lived bright X-ray nova. The explosion is produced when a stream of gas rushes toward a neuron star or a black hole.
A nova is different from a supernova (the explosion that ends a star’s life) because it does not completely destroy a star. The newly discovered black hole is estimated to be about 20,000 to 30,000 light-years away in the inner region of the galaxy.
Astronomers added that witnessing an event like the X-ray nova of Swift J1745-26 is very rare. Neil Gehrels, who works with NASA’s Goddard Space Flight Center in Greenbelt, Maryland, stated:
“Bright X-ray novae are so rare that they’re essentially once-a-mission events and this is the first one Swift has seen. This is really something we’ve been waiting for.
NBC News notes that, at its peak, the nova reached an intensity that was equivalent to the Crab Nebula. While the X-rays dimmed, the nova brightened in lower-energy emissions.
Additional observations by astronomers suggested that the black hole was at the center of the flare-up of radiation. Boris Sbarufatti, an astrophysicist from Milan’s Brera Observatory, who currently works with the Swift team, stated:
“The pattern we’re seeing is observed in X-ray novae where the central object is a black hole. Once the X-rays fade away, we hope to measure its mass and confirm its black hole status.”
The black hole is believed to be a part of a low-mass X-ray binary system. This system occurs when gas flows from a star into a disk around the black hole. It spirals inward and heats up significantly when it heads toward the center.
NASA scientists added that a cosmic glitch can disrupt this flow, causing it to accumulate in the outer portion of the disk. It builds up like water does behind a dam until the disk switches to a hotter and more ionized state. At that point, the gas rushes toward the center of the black hole, creating the rare X-ray nova, or star explosion, that NASA scientists observed.