Penn State astronomers using the world's largest radio telescope, at Arecibo, Puerto Rico, have discovered flaring radio emissions from an ultra-cool star, not much warmer than the planet Jupiter, shattering the previous record for the lowest stellar temperature at which radio waves were detected. The team from Penn State's Department of Astronomy and Astrophysics and the Center for Exoplanets and Habitable Worlds, led by Alex Wolszczan, the discoverer of the first planets ever found outside our solar system, has been using the giant 305-metre telescope to look for radio signals from a class of objects known as brown dwarfs. These objects are small, cold stars that bridge the gap between Jupiter-like giant planets and normal, more-massive, hydrogen-fusing stars. The astronomers hit the jackpot with a star named J1047+21, a brown dwarf 33.6 light years away in the constellation Leo, in a result that could boost the odds of discovering life elsewhere in the universe. Read more
Astronomers using the world's largest radio telescope, at Arecibo, Puerto Rico, have discovered flaring radio emission from an ultra-cool star, not much warmer than the planet Jupiter, shattering the previous record for the lowest stellar temperature at which radio waves were detected. Read more
Title: The Arecibo Detection of the Coolest Radio-flaring Brown Dwarf Authors: Matthew Route, Alex Wolszczan (Version, v2)
Radio detection provides unique means to measure and study magnetic fields of the coolest brown dwarfs. Previous radio surveys have observed quiescent and flaring emission from brown dwarfs down to spectral type L3.5, but only upper limits have been established for even cooler objects. We report the detection of sporadic, circularly polarized flares from the T6.5 dwarf, 2MASS J1047+21, with the Arecibo radio telescope at 4.75 GHz. This is by far the coolest brown dwarf yet detected at radio frequencies. The fact that such an object is capable of generating observable, coherent radio emission, despite its very low, ~900 K temperature, demonstrates the feasibility of studies of brown dwarfs in the meagerly explored LTY spectral range, using radio detection as a tool.