What is a white dwarf? Scientists predict the death of our solar system

Leading scientists have suggested that parts of our solar system will eventually meet their end as a result of a white dwarf star.

As the Sun, our solar system’s only star, becomes increasingly volatile, it will probably also destroy Earth.

Scientists from the University of Warwick have recently shared further insight into the future of solar systems like our own, thanks to their studies into white dwarf stars in other galaxies.

Although such a scenario is unlikely to happen for another six billion years, their findings have helped unlock more information about how white dwarf stars operate and what it could mean for planet Earth.

The study focused on three white dwarf stars that all behaved very erratically, highlighting the volatility of white dwarf stars.

The scientists also observed what happened to asteroids, planets and moons that came close to the white dwarfs, helping them reach the conclusions of their study. Their findings suggested that anything that came close would be destroyed.

“Previous research had shown that when asteroids, moons, and planets get close to white dwarfs, the huge gravity of these stars rips these small planetary bodies into smaller and smaller pieces,” said the study’s leader, Dr Amornrat Aungwerojwit.

An artist’s impression of the T Coronae Borealis star system, showing a red giant star and white dwarf orbiting each other (Nasa Goddard Space Flight Centre/PA)

What is a white dwarf star?

A white dwarf is the core of a dead star that has depleted all of its fuel and is slowly cooling down. They’re small in size, very dense, and not very easy to spot because they don’t burn as brightly as other stars.

Over the last few years, there have been a lot of breakthroughs in the studies of white dwarfs, including the discovery of two merged white dwarfs as well as a white dwarf that flickers on and off.

Stars up to eight times the size of our Sun usually become white dwarfs at the end of their lives, whereas stars with bigger masses turn into black holes or neutron stars.

To become a white dwarf, stars first turn into red giants, where they rapidly expand and begin to escape the pulls of gravity. What’s left behind after this is a white dwarf, an incredibly hot mixture of carbon, helium, and oxygen that will take billions of years to cool. In fact, scientists believe that no dwarf stars that have fully cooled exist yet because it takes so long.

The scientific community has widely accepted that this is the future of the Sun at the centre of our own solar system.

Reports claim that our Sun will enter this phase in around five billion years, consuming Mercury, Venus and potentially Earth as it expands.

Astronomers see white dwarf ‘switch on and off’ for the first time (Helena Uthas/Durham University)

How will Earth end?

There’s been some debate about whether Earth will also be destroyed as the Sun expands prior to becoming a white dwarf. However, the scientists behind the latest study appeared to suggest that could be the case.

Prof Boris Gaensicke, the study’s author, said: “The sad news is that the Earth will probably just be swallowed up by an expanding Sun before it becomes a white dwarf.”

Even if it didn’t, it wouldn’t be habitable because of its proximity to the sun.

He added: “For the rest of the solar system, some of the asteroids located between Mars and Jupiter, and maybe some of the moons of Jupiter may get dislodged and travel close enough to the eventual white dwarf to undergo the shredding process we have investigated.”

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