pulsars_leadart_final
An excess of gamma-rays coming from the center of the Milky Way is likely due to a population of pulsars – rapidly spinning, very dense and highly magnetized neutron stars that emit “beams” of gamma rays like cosmic lighthouses. The pulsars’ location in the oldest region of the galaxy suggests that they leach energy from companion stars, which prolongs the pulsars’ lifetime. The background image shows the galactic center as seen by NASA’s Chandra X-ray Observatory. NASA/CXC/University of Massachusetts/D. Wang et al.; Greg Stewart/SLAC National Accelerator Laboratory

NASA’s scientists have detected a powerful thermonuclear blast that came from outer space. According to their observations, the blast most likely came from the supernova remnant of a star that has collapsed.

The blast was detected by NASA’s Neutron Star Interior Composition Explorer (NICER) telescope. Scientists noted that NICER was able to spot it due to a sudden spike of X-rays earlier in August.

According to NASA, the X-ray burst was the brightest one spotted by NICER. After carrying out follow-up investigations, the space agency’s scientists were able to conclude that the blast originated from a distant pulsar known as SAX J1808.4-3658.

As explained by the agency, pulsars are the remains of a star that went supernova after collapsing under the weight of its own gravity. Despite causing a huge explosion, the star was not big enough to form into a black hole.

“This burst was outstanding,” Peter Bult, an astrophysicist at NASA’s Goddard Space Flight Center and the lead researcher of NICER’s latest discovery, said in a statement.

“We see a two-step change in brightness, which we think is caused by the ejection of separate layers from the pulsar surface, and other features that will help us decode the physics of these powerful events,” he added.

According to NASA, the X-ray burst from the pulsar produced as much energy in 20 seconds as the Sun does in almost 10 days. The scientist explained the burst was caused by helium that sunk beneath the surface of the pulsar and formed into a ball of carbon. This then caused the helium to erupt violently and cause a thermonuclear explosion from the pulsar’s surface.

“The helium settles out and builds up a layer of its own,” researcher Zaven Arzoumanian of NASA’s Goddard Space Flight Center explained. “Once the helium layer is a few meters deep, the conditions allow helium nuclei to fuse into carbon. Then the helium erupts explosively and unleashes a thermonuclear fireball across the entire pulsar surface.”

A study detailing NICER’s discovery and the scientists’ investigations on the X-ray burst was published in the Astrophysical Journal Letters.

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