Discovering a Neutron Star Speed Demon

Imagine a star spinning so fast, it completes 716 rotations in a single second. That's what scientists found when they studied a neutron star in a binary system called 4U 1820-30. This dead star, located 26, 000 light-years away, isn't just speedy – it's also explosive. Its surface bursts with thermonuclear blasts as powerful as atomic bombs. NASA's NICER telescope on the International Space Station helped make this discovery. Neutron stars form when massive stars run out of fuel and collapse under their own gravity. This leaves behind a tiny, super-dense star. The neutron star in 4U 1820-30 is part of a binary system with a white dwarf. This pair of stellar corpses is in a tight orbit, with the white dwarf completing a lap every 11 minutes.

The neutron star's incredible spin is due to the conservation of angular momentum. Just like an ice skater pulling in their arms to spin faster, the neutron star's rapid compression makes it spin quickly. It also gets a speed boost from matter it steals from its white dwarf companion. This stolen matter can pile up and explode in thermonuclear blasts. Scientists observed 15 of these explosions between 2017 and 2021 using NICER. The bursts made the neutron star up to 100, 000 times brighter than the sun. Understanding these extreme events helps scientists learn about the life cycles of binary star systems and the creation of elements in the universe.

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