Scientists have observed a white dwarf flashing up and down for the first time.
In the case of “unexpected” findings that don’t match existing understanding of the universe, researchers can observe how stars die, become bright and then darken.
It was seen through NASA’s telescopes which are usually used to hunt for exoplanets or distant worlds in other planetary systems.
White dwarfs are the final state of most stars: after burning the hydrogen that drives stars, they become dense packages that glow in the night sky.
They are roughly the size of the earth, but have a mass that is more similar to our sun.
It is known that the white dwarfs observed by the researchers add to or eat orbiting companion stars.
A loss of brightness has been observed within 30 minutes, a process previously seen only in white dwarfs accretion over days to months.
Since the brightness of the growing white dwarf is affected by the amount of material in the surroundings it eats, the researchers suspect something is interfering with its food supply.
University of Durham researchers hope the discovery will help them learn more about the physics behind accretion – in which objects such as black holes, white dwarfs and neutron stars feed on surrounding material from neighboring stars.
NASA’s Transiting Exoplanet Survey Satellite (Tess) observed the phenomenon in the white dwarf binary system TW Pictoris, located about 1,400 light-years from Earth.
TW Pictoris consists of a white dwarf feeding on a surrounding accretion disk powered by hydrogen and helium from its smaller companion star.
When a white dwarf eats – or gains – it becomes lighter.
The satellites allowed the team to see a sudden drop and never-before-seen increase in brightness in white dwarf accumulations on such a short timescale.
The researchers believe what they experienced could be a reconfiguration of the white dwarf’s surface magnetic field.
In “on” mode, when brightness is high, the white dwarf eats the accretion disc as usual.
Suddenly and suddenly, the system “turns off” and its brightness drops, astronomers observe.
The researchers say that in this case, the magnetic field rotates so fast that the barrier prevents fuel from the accretion disk from constantly falling onto the white dwarf.
During this phase, the amount of fuel the white dwarf can eat is regulated through a process called magnetgating.
Lead author dr. Simone Scaringi of the Center for Extragalactic Astronomy at the University of Durham said, “The brightness fluctuations observed in accretive white dwarfs are generally relatively slow, occurring over the time span of days to months.
“Seeing the brightness of TW Pictoris drop in 30 minutes is in itself extraordinary, as it has never been seen in any other accretionary white dwarf, and was completely unexpected from our understanding of how this system is supposed to feed through the accretion disk.
“Looks like life and death.
“This is truly a previously unrecognized phenomenon, and because we can make comparisons with similar behavior in much smaller neutron stars, it could be an important step towards a better understanding of the process by which other accretionary objects feed on the material around them. the role of the magnetic field in this process.”
The research, published in Nature Astronomy, was funded in the UK by Durham University.
The research team also includes the Italian National Institute of Astrophysics, the Astronomical Observatory of South Africa, the University of Cape Town and the University of the Free State, both also South Africa, Radboud University, Netherlands, University of Southampton, UK, and the university. Notre Dame, United States of America.
Additional reporting by agency
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