An accreting white dwarf displaying fast transitional mode switching

Accreting white dwarfs are often found in close binary systems with orbital periods ranging from tens of minutes to several hours. In most cases, the accretion process is relatively steady, significant modulations only occurring on time-scales ~days or longer. Here, we report discovery abrupt drops optical luminosity accreting dwarf system TW Pictoris by factors up 3.5 as short 30 minutes. The light curve this obtained Transiting Exoplanet Survey Satellite (TESS) clearly displays fast switches between two distinct intensity modes that likely track changing mass rate onto dwarf. low mode, also magnetically-gated bursts, which implies a weak magnetic field truncates inner disk at co-rotation radius mode. properties mode switching observed appear analogous those transitional millisecond pulsars, where similar transitions occur, although timescales ~tens seconds. Our establishes previously unrecognised phenomenon and suggests tight link physics governing neutron stars.