A dead star may have a planet orbiting it, scientists think, giving a glimpse of what the future of the solar system might look like billions of years from now – and even hinting that life may be able to evolve again.

Researchers at University College London (UCL) were studying a white dwarf lying some 117 light years away from Earth when they noticed that a ring of debris around the star was behaving oddly.

They theorised that the circle of space rocks was caught in the gravitational pull of a nearby planet.

Crucially, if the planet exists, it would be orbiting in the “Goldilocks Zone” where it is neither too hot, nor too cold, for liquid water to exist, meaning that life could form.

The Sun is expected to become a white dwarf around seven billion years from now, after expanding in a red giant phase which is likely to engulf Mercury, Venus and probably Earth.

Some experts believe that Earth could survive the red giant phase, although all life would be extinguished in the immense heat.

If a planet does exist orbiting the white dwarf, the researchers say it is more likely to be a new addition, rather than the remnant of a body like Earth.

More than enough time for life to evolve

The planet is in a zone which would be habitable for at least two billion years, more than long enough for life to evolve. It took just 800,000 years for life to get going on Earth after the planet formed.

Professor Jay Farihi, the lead author of the study, said: “Since our Sun will become a white dwarf in a few billion years, our study provides a glimpse into the future of our own solar system.

“This is the first time astronomers have detected any kind of planetary body in the habitable zone of a white dwarf.

“The possibility of a planet in the habitable zone is exciting and also unexpected, we were not looking for this.”

The vast majority of stars become white dwarfs, although the largest explode and become either black holes or neutron stars.

Scientists used ground and space-based telescopes

In the new study, UCL researchers measured light from the white dwarf using data from ground and space-based telescopes.

They were surprised to find marked dips in light corresponding to 65 evenly spaced clouds of planetary debris orbiting the star every 25 hours.

They concluded the dimming of the star’s light every 23 minutes suggested the structures were kept in such a precise arrangement by a nearby planet.

However, the scientists cautioned that more information was needed in order to confirm the presence of a planet.

The study was published in Monthly Notices Of The Royal Astronomical Society.