A Milky Way-surveying spacecraft has discovered a planet 12 times more massive than Jupiter, along with a brown dwarf, both orbiting stars smaller than the sun. The European Space Agency’s Gaia spacecraft, responsible for the discovery, is now retired due to running out of fuel.
The exoplanet, dubbed Gaia-4b, and its brown dwarf companion, Gaia-5b, are 244 and 134 light-years away from Earth respectively. Scientists have confirmed their existence after verification by other instruments.
“This discovery is an exciting tip-of-the-iceberg for the exoplanet discoveries we can expect from Gaia in the future,” said Matthew Standing, an ESA research fellow. The number of confirmed exoplanets has reached 5,800, with thousands more candidates under review.
Gaia-4b orbits its star over 570 Earth-days and is considered a super-Jupiter planet, a relatively cold gas giant. Its host star is estimated to be 64% the mass of the sun, making it one of the most massive planets known to orbit a small star.
The brown dwarf companion is about 21 times more massive than Jupiter and orbits its smaller star in a slightly shorter Earth-year. Despite not meeting the criteria for a star, it’s an impressive object with a mass equivalent to around 318 Earths.
The discovery marks Gaia’s first independent success using the “wobble” technique, or astrometry. The spacecraft has used optical telescopes to scan the sky since its launch in 2013 and has provided precision data that may lead to thousands of new discoveries.
Source: https://mashable.com/article/exoplanet-brown-dwarf-discoveries