Recent research in the Milky Way reveals a neutron star spinning at an incredibly high speed, making 716 rotations each second. This discovery makes it one of the fastest-spinning objects ever recorded in the universe.
Researchers at DTU used an X-ray telescope on the International Space Station (ISS) to study this unusual star. Located in the Sagittarius constellation, this neutron star is part of an “X-ray binary star system,” named 4U 1820-30, positioned near the center of our galaxy. In this system, two stars orbit each other, and the neutron star’s companion is a white dwarf roughly the same size as Earth, circling the neutron star every 11 minutes—the shortest orbital period known for such systems.
Dr. Gaurava K. Jaisawal, a senior scientist at DTU Space and first author of a recent article in the Astrophysical Journal, explains the discovery: “While studying thermonuclear explosions from this system, we noticed unusual oscillations indicating the neutron star rotates at an incredible speed of 716 times per second around its central axis.”
This neutron star was examined with NASA’s NICER X-ray telescope, equipped with DTU’s star-tracking technology, which keeps the telescope aimed precisely at the distant, small neutron stars across the Milky Way. NICER’s advanced technology enabled scientists to capture clear details of this neutron star’s remarkable speed and behavior.
What Exactly is a Neutron Star?
A neutron star forms when a massive star explodes in a supernova, leaving behind an extremely dense “dead star.” Such stars are the densest observable objects in space. Even though this neutron star is only about 12 km in diameter, it has a mass 1.4 times that of the Sun. Found some 26,000 light-years from Earth, it’s much farther than Earth’s closest star, Proxima Centauri, which is only 4.3 light-years away.
Thermonuclear Bursts Like Atomic Bombs
Because of its intense gravitational pull, this neutron star draws in material from its companion white dwarf star. When enough material builds up, it triggers a powerful thermonuclear burst on the neutron star’s surface, similar in intensity to an atomic bomb. These bursts make the neutron star shine up to 100,000 times brighter than the Sun, unleashing immense energy.
Associate Professor Jerome Chenevez, also part of the DTU Space team, adds, “These bursts are extreme events. By examining them closely, we learn more about the complex life cycles of binary star systems and the formation of elements across the universe.”
Observations and Findings with NICER
Between 2017 and 2021, researchers observed 15 intense thermonuclear X-ray bursts from 4U 1820-30. One of these bursts revealed a signal called a “thermonuclear burst oscillation,” occurring at a frequency of 716 Hz. This frequency matches the neutron star’s spin, confirming its extraordinary rotation speed.
Future observations may confirm 4U 1820-30 as one of the fastest-spinning objects ever observed, similar only to another neutron star, PSR J1748-2446.
