PARIS: A European Space Agency satellite tasked with tracking down exoplanets has made its first big catch, a world so hot that its atmosphere could melt iron, astrophysicists have reported.

Launched into Earth orbit in December, the CHEOPS space-based telescope spotted the gas giant circling close to one of the hottest known stars with a planetary system, according to a study published last week.

Some 322 light years away in the constellation Libra, WASP-189b is so close to its host star that it orbits in less than three days. It is too far away from Earth to see directly, but can be detected in other ways.

When a planet passes between its star and an observer - whether an astronomer on land or a telescope in space - it dims the star's light by a tiny but measurable amount. This "transit" method has detected the vast majority of exoplanets discovered so far. NASA's Kepler spacecraft used it to find thousands of candidates from 2009 to 2013.

Exoplanets - any planet outside our solar system - were first confirmed to exist in 1995 by two Swiss astronomers, Michel Mayor and Didier Queloz, an exploit that earned them a physics Nobel last year. Queloz is among the more than 100 co-authors of the new study, published last week in the journal Astronomy & Astrophysics. There are 4,284 confirmed exoplanets as of September 29, according to the NASA Exoplanet Archive, and at least as many likely candidates.