James Webb Space Telescope could unlock secrets of newly discovered Earth-sized planet

Astronomers have discovered a brand new planet the size of Earth, with the next big job now tasked to the $10 billion James Webb Space Telescope.

The planet was found by astronomers from the University of Liège, led by Michaël Gillon.

Dubbed the SPECULOOS project [Search for Planets EClipsing ULtra-cOOl Stars], the team discovered the new planet roughly 55 light-years from our planet.

Orbiting an 'ultra-cool dwarf' star that is the size of Jupiter, and half the temperature of our Sun, the planet has been named SPECULOOS-3 b.

It's believed to be tidally locked, meaning it doesn't spin on an axis like Earth. It's more like our Moon, in that sense.

With the star being cooler and smaller that the Sun, scientists have estimated that their lifespan is more than one hundred times longer than our solar system's star. That's roughly 100 billion years.

The long life span, scientists believe, could offer opportunities for life on orbiting planets to develop.

CGI of the James Webb Space Telescope floating through space (NASA/Getty Stock Images)

Amaury Triaud, Professor of Exoplanetology at the University of Birmingham said: “The discovery of SPECULOOS-3 shows our worldwide network functions well and is ready to detect yet more rocky worlds orbiting very low mass stars.

"While ultra-cool dwarf stars are cooler and smaller than our sun, their lifespan is over a hundred times longer – around 100 billion years – and they are expected to be the last stars still shining in the Universe.”

Gillon said: "SPECULOOS-3 b is practically the same size as our planet. A year - i.e. an orbit around the star - lasts around 17 hours. Days and nights, on the other hand, should never end.

"We believe that the planet rotates synchronously, so that the same side, called the day side, always faces the star, just like the Moon does for the Earth. On the other hand, the night side hand, would be locked in endless darkness."

Artist's view of exoplanet SPECULOOS-3 b orbiting its star. The planet is as big as the Earth. (Lionel Garcia)

Now, it's time for NASA's James Webb Space Telescope (JWST) to get involved, which can deliver important insights into the planet’s surface mineralogy, and the potential for an atmosphere.

"With the JWST, we could even study the mineralogy of the planet's surface," says Elsa Ducrot, a former researcher at the University of Liège now based at Paris Observatory.

And Dr Georgina Dransfield, a former PhD student at the University of Birmingham, said: "The small size of ultra-cool dwarfs makes it easier to detect small planets. SPECULOOS-3b is special in that its stellar and planetary properties make it an optimal target for JWST, which is capable to get information about the composition of the rocks that make its surface."

Artist's view of exoplanet SPECULOOS-3 b orbiting its star (NASA/JPL-Caltech)

Gillon says: "This discovery demonstrates the ability of our SPECULOOS-North observatory to detect Earth-sized exoplanets suitable for detailed study. And this is just the beginning.

"Thanks to the financial support of the Walloon Region and the University of Liège, two new telescopes, Orion and Apollo, will soon join Artemis on the plateau of the Teide volcano in Tenerife, to speed up the hunt for these fascinating planets."