An exoplanet discovered nearly 130 light years away appears to be 13 times larger than Jupiter and is undergoing nuclear fusion at its core. The newly discovered world also exists at the boundary between a planet and a brown dwarf star.
Its discovery could help scientists clarify how they classify objects that are either a brown dwarf or an extrasolar planet. The discovery is also the first exoplanet to be directly imaged, thanks to an international team of scientists and the European Space Agency (ESO)’s Gaia spacecraft.
“This discovery is also very significant because it shows that we can now directly characterize the atmospheres of these exoplanets where we know from previous studies that they most commonly reside, at roughly two to four times our Earth/Sun distance,” said Sasha Hinkley of the University of Exeter in a statement. She led the scientific team behind the discovery.
The exoplanet orbits the star HD206893, which is roughly 30 per cent larger than our own Sun. Astronomers observing the system discovered a brown dwarf, known as HD206893B, orbiting the star in 2017. Long-term monitoring of the system indicated an inner and lower-mass companion.
Scientists using ESO’s Very Large Telescope discovered the exoplanet, called HD206893c, orbiting roughly 4.8 million kilometres from the star. This is roughly halfway between the orbits of Mars and Jupiter, but with a mass greater than Jupiter.
The discovery is one of the first exoplanets to be found because its existence was hinted at by the astrometric motions of its host star. A statement from the University of Exeter describes the discovery as “a breakthrough in the quest to discover new, distant worlds.”
“The discovery of HD206893c is a really important moment for the study of exoplanets, as ours may be the first direct detection of a ‘Gaia exoplanet,’” said Hinkley.
The exoplanet itself is equally as fascinating as how it was discovered. Researchers found clear signs that the planet is “brightening” as nuclear fusion burns deuterium, also known as heavy hydrogen, in its core. Deuterium is a stable isotope of hydrogen that carries a neutron. The research was published in the journal Astronomy & Astrophysics.