Earth-sized planet spotted orbiting small star with 100 times sun’s lifespan

An artist’s impression of Speculoos-3b orbiting its star, an ultra-cool red dwarf. Photograph: Nasa/JPL-Caltech

Astronomers have discovered a new Earth-sized planet orbiting a small, cool star that is expected to shine for 100 times longer than the sun.

The rocky world, called Speculoos-3b, is 55 light years from Earth and was detected as it passed in front of its host star, an ultra-cool red dwarf that is half as hot as the sun and 100 times less luminous.