"We found that 51 Eridani is surrounded by warm dust that indicates the presence of an asteroid belt," said Patel. "Finding dust around a star is like seeing a large signpost that tells us there might be a planet," he added. "This is because the dust is usually created when lots of large asteroids collide and destroy each other, usually pushed around by a large planet - like 51 Eridani b."
Patel led NASA's Wide-field Infrared Survey Explorer (WISE) to search for any thermal glow that dust and ice grains resulting from collisions among asteroids and comets in the Solar System can produce. His previous work identifying recycled planetary dust, known as "debris disks," around close to a hundred other star systems, puts the discovery of the exoplanet in context.
In addition to being the faintest planet ever imaged, it's also the coldest - 400 Celsius, whereas others are around 700 Â°C - and features the strongest atmospheric methane signal on record.