Researchers led by Durham University in the UK have utilized NASA’s Transiting Exoplanet Survey Satellite (TESS) to observe this phenomenon they describe as extraordinary.
White dwarfs are celestial objects formed when low- and medium-mass stars “die” (exhausting their nuclear fuel). They are approximately the size of Earth but have a mass close to that of the Sun.
The white dwarf studied by the team of scientists is part of the binary white dwarf system TW Pictoris, located about 1,400 light-years from Earth.
When a white dwarf “feeds,” it becomes brighter.
TW Pictoris consists of a white dwarf that draws fuel from an accretion disk supplied with hydrogen and helium from its smaller companion star. As the white dwarf “feeds,” it becomes brighter.
From TESS observations, scientists noted that the brightness of the white dwarf diminished over approximately 30 minutes—this process typically occurs over several days to months in other white dwarfs.
The brightness of this white dwarf is influenced by the amount of material it consumes from its surroundings. Therefore, researchers suggest that something is obstructing its food supply.
The research team stated that they had never witnessed such a rapid decrease and increase in brightness in a white dwarf before.
In fact, the flow of material from the companion star to the white dwarf’s accretion disk is relatively stable, so it should not affect the brightness of these stars.
In the case of TW Pictoris, researchers believe they are observing a reconfiguration of the white dwarf’s surface magnetic field.
The researchers explained that in the “off” mode, the magnetic field of the white dwarf spins so fast that a centrifugal barrier prevents material from the accretion disk from continuously falling onto it. After some time, everything stabilizes, and the brightness of the white dwarf returns to its original level.
“This is truly a phenomenon that has never been recognized before. It could be an important step in helping us better understand how other accreting objects consume surrounding material and the crucial role of magnetic fields in this process,” said the lead author of the study, Dr. Simone Scaringi, from the Center for Extragalactic Astronomy.
Since white dwarfs are quite common in the universe, astronomers hope to search for other examples of this behavior in future research projects.
