ZTF J1813+4251 is a 51-minute-orbital-period, fully eclipsing binary system consisting of a star with a temperature comparable to that of the Sun but a density 100 times greater, accreting onto a white dwarf star. An artist’s illustration shows a white dwarf (right) circling a larger, Sun-like star (left) in an ultra-short orbit, forming a cataclysmic binary system. Image credit M. Weiss / Harvard & Smithsonian’s Center for Astrophysics. A...
