Science

Record-breaking white dwarf star completes a full rotation once every 25 SECONDS


Getting in a spin: Record-breaking white dwarf star completes a full rotation once every 25 SECONDS – four seconds faster than the previous record-holder

  • The star, called J0240+1952, is the fastest spinning confirmed white dwarf
  • It is the same size of Earth, but is thought to be at least 200,000 more massive
  • The star is pulling gaseous plasma from a nearby companion star and flinging it into space at speeds of around 1,864 miles/second (3,000 kilometres/second)










A white dwarf star has broken records after scientists discovered that it completes a full rotation once every 25 seconds.

The star, called LAMOST J024048.51+195226.9 (or J0240+1952 for short), was analysed by researchers from the University of Warwick, who say it is the fastest spinning confirmed white dwarf.

The previous record holder was a white dwarf that completed a rotation in just over 29 seconds, making J0240+1952 20 per cent faster.

Dr Ingrid Pelisoli, who led the study, said: ‘J0240+1952 will have completed several rotations in the short amount of time that people take to read about it, it is really incredible.’

The star, called LAMOST J024048.51+195226.9 (or J0240+1952 for short), was analysed by researchers from the University of Warwick, who say it is the fastest spinning confirmed white dwarf

The star, called LAMOST J024048.51+195226.9 (or J0240+1952 for short), was analysed by researchers from the University of Warwick, who say it is the fastest spinning confirmed white dwarf

WHAT IS A WHITE DWARF? 

A white dwarf is the remains of a star that has run out of nuclear fuel.

Stars larger than 10 times the mass of the sun suffer a violent supernova at the end of their lives, but a more gentle end awaits sun-like stars. 

When stars like the sun come to the ends of their lives they exhaust their fuel, expand as red giants and later expel their outer layers into space.

The hot and very dense core of the former star – a white dwarf – remains.

White dwarfs contain approximately the mass of the sun but have roughly the radius of Earth. 

A white dwarf is a star that has burned up all of its fuel, and is beginning to shed its outer layers.

This particular white dwarf is around the same size of Earth, but is thought to be at least 200,000 more massive.

In the study, the team studied J0240+1952 using the highly sensitive HiPERCAM instrument on the 10 metre-wide Gran Telescopio Canarias in La Palma – the world’s largest functioning optical telescope.

Their analysis indicates that the white dwarf star is pulling gaseous plasma from a nearby companion star and flinging it into space at speeds of around 1,864 miles/second (3,000 kilometres/second).

This gives the star an extremely quick spin of just 25 seconds. For comparison, Earth complete one spin in 24 hours!

‘The rotation is so fast that the white dwarf must have an above average mass just to stay together and not be torn apart,’ explained Dr Pelisoli.

‘It is pulling material from its companion star due to its gravitational effect, but as that gets closer to the white dwarf the magnetic field starts to dominate.

‘This type of gas is highly conducting and picks up a lot of speed from this process, which propels it away from the star and out into space.’

J0240+1952 is one of only two stars with this magnetic propeller system discovered in over 70 years, according to the team.

Material was first observed being flung out of the star in 2020, although astronomers were unable to confirm the presence of a rapid spin – a key indicator of a magnetic propeller – as the pulsations were too fast and dim for other telescopes to spot.

Professor Tom Marsh co-author of the study, added: ‘It’s only the second time that we have found one of these magnetic propeller systems, so we now know it’s not a unique occurrence. 

‘It establishes that the magnetic propeller mechanism is a generic property that operates in these binaries, if the circumstances are right.

‘The second discovery is almost as important as the first as you develop a model for the first and with the second you can test it to see if that model works. 

‘This latest discovery has shown that the model works really well, it predicted that the star had to be spinning fast, and indeed it does.’ 

WHAT WILL HAPPEN TO EARTH WHEN THE SUN DIES?

Five billion years from now, it’s said the Sun will have grown into a red giant star, more than a hundred times larger than its current size. 

Eventually, it will eject gas and dust to create an ‘envelope’ accounting for as much as half its mass.

The core will become a tiny white dwarf star. This will shine for thousands of years, illuminating the envelope to create a ring-shaped planetary nebula.

Five billion years from now, it's said the Sun will have grown into a red giant star, more than a hundred times larger than its current size

Five billion years from now, it’s said the Sun will have grown into a red giant star, more than a hundred times larger than its current size

While this metamorphosis will change the solar system, scientists are unsure what will happen to the third rock from the Sun.

We already know that our Sun will be bigger and brighter, so that it will probably destroy any form of life on our planet.

But whether the Earth’s rocky core will survive is uncertain. 





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