For the first time ever, a radio telescope has detected an elusive, cold, faint “super-planet”. It was the Low-Frequency Array (or LOFAR) radio telescope in the Netherlands that first discovered the brown dwarf that has been named BDR J1750+3809 (nicknamed Elegast). The International Gemini Observatory in Hawaii and Chile in addition to the NASA Infrared Telescope Facility that is operated by the University of Hawai’i then confirmed its existence.
Brown dwarfs can either be failed stars (because they’re too tiny to be considered an actual star) or super-planets (because they’re too big to be considered a planet). In fact, since brown dwarfs are much too small to form into stars, they don’t have the same amount of nuclear fusion reactions that bright stars have, although they can release some light at radio wavelengths. That is the reason why they are colder and dimmer than actual stars (like our sun).
With that being said, it is also much more difficult to spot them in space. That’s why the discovery of Elegast was so exciting as it is the first brown dwarf that has ever been discovered by a radio telescope as they are usually detected by infrared sky surveys.
In a statement provided by the University of Hawai’i, Michael Liu, who is a researcher from the University of Hawai’i Institute for Astronomy and a co-author of the study, noted, “This work opens a whole new method to finding the coldest objects floating in the sun's vicinity, which would otherwise be too faint to discover with the methods used for the past 25 years.”
Harish Vedantham, who is an astronomer from the Netherlands Institute for Radio Astronomy (ASTRON) and the lead author of the study, stated, “We asked ourselves, ‘Why point our radio telescope at catalogued brown dwarfs?’” “Let's just make a large image of the sky and discover these objects directly in the radio.” I bet they’re glad they did or else they might not have made the first ever discovery of a brown dwarf with their radio telescope. (An artist’s impression of Elegast can be seen here.)
By having the LOFAR instrument detect the brown dwarf, this may help with the detection of other space objects in the future like gas giant exoplanets that wouldn’t be found with infrared surveys because they’re too faint or cold.
Their study was published in The Astrophysical Journal Letters where it can be read in full.