<p>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.</p>.<p>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.</p>.<p>"We estimate the temperature of WASP-189b to be 3,200 degrees Celsius (5,800 degrees Fahrenheit)," said lead author Monika Lendl, a scientist at the University of Geneva.</p>.<p>"This object is one of the most extreme planets we know so far," she added, describing it as "very exotic".</p>.<p>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.</p>.<p>It is too far away from Earth to see directly, but can be detected in other ways.</p>.<p>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.</p>.<p>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.</p>.<p>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.</p>.<p>Queloz is among the more than 100 co-authors of the new study, published last week in the journal Astronomy & Astrophysics.</p>.<p>There are 4,284 confirmed exoplanets as of September 29, according to the NASA Exoplanet Archive, and at least as many likely candidates.</p>.<p>The vast majority are bigger than those of our solar system: 1,339 so-called ice giants, 1,457 Neptune-like gas giants, and 1320 "super Earths" with masses many times greater than the rock we call home.</p>.<p>There are relative few -- 162 -- terrestrial planets with Earth-like mass, and of those only a handful are in a "temperate" zone that would support liquid water, a key ingredient for life as we know it.</p>.<p>WASP-189b is unusual in that it does not reflect a lot of star light.</p>.<p>"Instead, most of the starlight gets absorbed by the planet, heating it up and making it shine," said Lendl.</p>.<p>WASP-189b's star is bigger than the Sun, and about 2,000 degrees Celsius hotter, the researchers reported.</p>.<p>Because it is so hot, the star appears blue and not yellow-white like the Sun.</p>.<p>Several studies estimate there could be a trillion exoplanets in our galaxy alone. Indeed, there may be as many or more exoplanets in the universe as there are stars.</p>.<p>CHEOPS -- an acronym for CHaracterising ExOPlanet Satellite -- is in orbit 700 kilometres (435 miles) from Earth.</p>
<p>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.</p>.<p>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.</p>.<p>"We estimate the temperature of WASP-189b to be 3,200 degrees Celsius (5,800 degrees Fahrenheit)," said lead author Monika Lendl, a scientist at the University of Geneva.</p>.<p>"This object is one of the most extreme planets we know so far," she added, describing it as "very exotic".</p>.<p>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.</p>.<p>It is too far away from Earth to see directly, but can be detected in other ways.</p>.<p>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.</p>.<p>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.</p>.<p>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.</p>.<p>Queloz is among the more than 100 co-authors of the new study, published last week in the journal Astronomy & Astrophysics.</p>.<p>There are 4,284 confirmed exoplanets as of September 29, according to the NASA Exoplanet Archive, and at least as many likely candidates.</p>.<p>The vast majority are bigger than those of our solar system: 1,339 so-called ice giants, 1,457 Neptune-like gas giants, and 1320 "super Earths" with masses many times greater than the rock we call home.</p>.<p>There are relative few -- 162 -- terrestrial planets with Earth-like mass, and of those only a handful are in a "temperate" zone that would support liquid water, a key ingredient for life as we know it.</p>.<p>WASP-189b is unusual in that it does not reflect a lot of star light.</p>.<p>"Instead, most of the starlight gets absorbed by the planet, heating it up and making it shine," said Lendl.</p>.<p>WASP-189b's star is bigger than the Sun, and about 2,000 degrees Celsius hotter, the researchers reported.</p>.<p>Because it is so hot, the star appears blue and not yellow-white like the Sun.</p>.<p>Several studies estimate there could be a trillion exoplanets in our galaxy alone. Indeed, there may be as many or more exoplanets in the universe as there are stars.</p>.<p>CHEOPS -- an acronym for CHaracterising ExOPlanet Satellite -- is in orbit 700 kilometres (435 miles) from Earth.</p>