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Astronomers have found an ultra-cool brown dwarf called T8 Dwarf WISE J062309.94−045624.6 that is the coldest star-like body on record to emit radio waves. Brown dwarfs are often referred to as "failed stars" because they are larger than gas giants but still smaller than typical stars. This particular brown dwarf has a temperature of around 800 degrees Fahrenheit (425 degrees Celsius), making it much cooler than our Sun, which has a temperature of about 10,000 degrees Fahrenheit (5,500 degrees Celsius).

Although there have been colder brown dwarfs discovered with temperatures as low as 10 degrees Fahrenheit (minus 23 degrees Celsius), they haven't been observed emitting radio waves. It is rare to find ultracool brown dwarfs producing radio emissions because their dynamics typically don't generate the magnetic fields necessary for radio emissions to be detectable from Earth. Therefore, the detection of radio waves from this brown dwarf at such a low temperature is a significant and intriguing discovery.

Studying brown dwarfs is important because they lack the mass required for nuclear fusion to occur in their cores, which is the defining process for main-sequence stars. Understanding the properties and behaviors of brown dwarfs can help scientists determine the boundary between gas giant planets and stars more accurately.

T8 Dwarf WISE J062309.94−045624.6 was first observed by scientists at the California Institute of Technology (Caltech) using the Wide-field Infrared Survey Explorer (WISE) in 2011. It is located approximately 37 light-years away from Earth and has a size ranging from 65% to 95% that of Jupiter, the largest planet in our solar system. Despite being smaller than Jupiter, the brown dwarf is much more massive, with a mass estimated to be between 4 and 44 times that of Jupiter.

The generation of magnetic fields and radio waves in main-sequence stars like the Sun is relatively well understood. However, the internal dynamics of brown dwarfs, including their ability to produce radio waves, are not as well studied. Only about 10% of known brown dwarfs are observed to emit radio waves. Scientists hypothesize that the rapid rotation of some ultracool brown dwarfs could generate strong magnetic fields. When these fields interact with the ionized atmosphere of the brown dwarf, it creates an electric current, leading to the production of radio waves.

Further research on T8 Dwarf WISE J062309.94−045624.6 and other ultracool brown dwarfs could help unravel this mystery and provide insights into the evolution of stars and their magnetic field generation. The analysis of this brown dwarf's radio emissions was conducted using the CSIRO ASKAP telescope in Western Australia, with additional confirmations from the Australia Telescope Compact Array and the MeerKAT telescope in South Africa.

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