European astronomers announced Monday the discovery of 32 new planets outside our solar system, bringing the number of known exoplanets to more than 400.

The newly found planets include six that have a mass of only a few times the size of the Earth, an encouraging sign in the quest for Earth-like worlds that could harbor life.

The discovery was made with the so-called High Accuracy Radial Velocity Planet Searcher or HARPS, a spectrograph for the European Southern Observatory's (ESO) 3.6-meter telescope at La Silla, Chile.

"HARPS is a unique, extremely high precision instrument that is ideal for discovering alien worlds," said Stephane Udry, a researcher at the University of Geneva in an ESO statement.

"We have now completed our initial five-year program, which has succeeded well beyond our expectations," said Udry.

Over the past five years, HARPS has spotted over 75 exoplanets, including 24 of the 28 planets known with masses below 20 Earth masses. The ESO said the discovery cemented "HARPS's position as the world's foremost exoplanet hunter."