Indeed at the time its productivity was similarly compared to the rest of the world's minor planet hunters, and even rivals computerized searches from the 1990s and 2000s.

"There is one other possibility, namely that planet hunters have discovered a new class of objects," he said.

Learn why this planet is so puzzling and how planet hunters make amazing discoveries like these.

Planet Hunt: Extrasolar planet hunters have found more than 450 planets orbiting more than 380 distant stars.

Iota Horologii b was announced in the summer of 1999 as the first planet found by a team of planet hunters led by Martin Kürster.

The discovery of Kepler 20e and Kepler 20f may be an encouraging sign that planet hunters would someday succeed in finding other Earth-like planets.

Despite the great successes of planet hunters with Doppler spectroscopy of the host star, exomoons cannot be found with this technique.

The discovery raises the hopes of planet hunters that if they keep working they will find more and more potentially habitable systems like our own.

"This is a really exciting time for planet hunters."

The radial-velocity method has been by far the most productive technique used by planet hunters.