The fastest-spinning white dwarf ever seen rotates once every 25 seconds.
The sun rotates once each month and Earth once each day. But a white dwarf star 2,000 light-years afar spins every 25 seconds, defeating the former champion by five seconds. As a result, it is the fastest-spinning star of any kind ever seen.
A White Dwarf is extraordinarily dense, being around the size of Earth but about the mass of the sun. The surface gravity of the star is so strong that if you dropped a stone from a few feet away, it would crash against the surface at thousands of kilometers per hour. The average white dwarf spins for hours or days. LAMOST J0240+1952 is the name of the fast-spinning white dwarf.
On the night of August 7, astronomer Ingrid Pelisoli of the University of Warwick in Coventry, England, and her coworkers saw a periodic blip of light from the faint couple. The blip occurred every 24.93 seconds, exposing the white dwarf star’s world-record spin cycle.
The sole known contender for the star is an even faster-spinning object in orbit around the blue star HD 49798. However, the form of that fast rotator is unknown, with some new research indicating that it is most likely a neutron star rather than a white dwarf.