The fastest-spinning white dwarf ever seen rotates once every 25 seconds /sciencenews. org/

The sun turns once a month and the Earth once a day, but a white dwarf star 2,000 light-years away spins every 25 seconds, beating the old champ by five seconds. That makes it the fastest-spinning star of any sort ever seen — unless you consider such exotic objects as neutron stars and black holes, some of which spin even faster, to be stars (SN: 3/13/07).  …

more: sciencenews.org/article/fastest-spinning-white-dwarf-star-rotation-speed