Using the Low-Frequency Array (LOFAR) radio telescope astronomers have discovered a new brown dwarf, a substellar object not quite massive enough to fuse hydrogen in its core. It is the first substellar object to be discovered through radio observations. Sci News reported this.
The newly-detected object, named BDR J1750+3809, is a cold brown dwarf of spectral type T6.5.
Nicknamed Elegast, the object is located 212 light-years away in the constellation of Hercules.
BDR J1750+3809 is the first object of its kind to be directly identified in radio images.
“Radio waves emitted by brown dwarfs carry information about their magnetic field strength,” said lead author Dr. Harish Vedantham, an astronomer in ASTRON and the Kapteyn Astronomical Institute at the University of Groningen, and colleagues.
“LOFAR’s low frequency of observation makes it sensitive to magnetic fields comparable to that of a fridge magnet, which is within the range postulated to exist on the coldest brown dwarfs and large exoplanets.”
“We could not have picked out BDR J1750+3809 in our standard radio images from among the crowd of millions of galaxies, but the object immediately stood out when we made circularly polarized images,” said co-author Dr. Tim Shimwell, an astronomer in ASTRON and Leiden Observatory.
The astronomers then used infrared follow-up observations from the Gemini telescope and NASA’s Infrared Telescope Facility to confirm that BDR J1750+3809 was indeed a cold brown dwarf.
“These observations really highlight the versatility of Gemini, and in particular the little-used ‘keyhole’ imaging capability of Gemini’s GNIRS spectrograph,” said co-author Dr. Trent Dupuy, an astronomer at Gemini Observatory and the University of Edinburgh.