Astronomers have spotted signs of a possible exoplanet - named Luhman 16AB - in a nearby brown dwarf system at 6.6 light years from earth. (One light year is equal to about 9.5 trillion km).
So far, only eight exoplanets have been discovered and, according to astronomers, Luhman 16AB could well be the first alien one discovered using astrometry.
To substantiate their claim, a team of astronomers led by Henri Boffin of the European Southern Observatory (ESO) used the Very Large Telescope Interferometer (VLTI) situated in Chile to take astrometric measurements of brown dwarfs.
"We were able to measure the positions of these two objects with a precision of a few milli-arcseconds. That is like a person in Paris being able to measure the position of someone in New York with a precision of 10 cm," said Boffin in the paper, published in the journal Astronomy and Astrophysics.
The team discovered that both brown dwarfs have a mass 30 to 50 times the mass of Jupiter. Because their mass is so low, they take about 20 years to complete one orbit around each other, the astronomers said.
Boffin's team also discovered slight disturbances in the orbits of these brown dwarfs which, according to them, could be owing to an alien planet around one of the two brown dwarfs.
"Further observations are required to confirm the existence of a planet but it may well turn out that the closest brown dwarf binary system to the sun turns out to be a triple system," Boffin added.
Brown dwarfs are sometimes called failed stars because they are bigger than planets but don't have enough mass to kick-off nuclear fusion at their core, says the paper.
The brown dwarfs were spotted in data from NASA's Wide-field Infrared Survey Explorer (WISE) spacecraft, which took about 1.8 million images of asteroids, stars and galaxies during its ambitious 13-month mission to scan the entire sky.
The brown dwarf system is slightly more distant than Barnard's star, a red dwarf that is six light years away from earth and was first spotted in 1916.