An illustration of a star going supernova. Depositphotos.

Scientists find a star barely hotter than a pizza oven

Okay, now this is interesting.


Now this is very cool. Scientists have found a star that they say is barely hotter than a pizza oven.

Within the celestial hierarchy, a unique brown dwarf, WISE J0623, earns a remarkable distinction as the coldest star detected to emit radio waves. This relatively small cosmic body is far from an ordinary star but too gigantic to be a planet.

Scientists find a star barely hotter than a pizza oven

Despite its similar size to Jupiter, WISE J0623 houses a potent magnetic field dwarfing our Sun’s. With pulsed radio emissions detected from this star, it’s added to the exclusive group of ultra-cool dwarfs producing recurrent radio bursts.

Tuning Into Cosmic Radio Signals

It may shock you to learn that, among the over 100 billion stars in the Milky Way, radio waves have been detected from fewer than 1,000. Why? Radio waves and optical light are the outcomes of distinct physical processes.

Contrasting thermal radiation from a star’s hot exterior, radio emissions result from speeding electrons interacting with magnetized gas around the star. By studying radio emissions, scientists gain insight into stars’ atmospheres and magnetic fields, potentially shedding light on life prospects on surrounding planets.


Shedding New Light on Dim Stars

Improved sensitivity and coverage of contemporary radio telescopes are key to detecting less luminous stars, including cool brown dwarfs like WISE J0623. Historically, radio telescopes’ sensitivity was only sufficient to identify exceptionally bright sources.

With a temperature of approximately 700 Kelvin, or 420℃, WISE J0623 is on par with a commercial pizza oven – quite hot from our perspective, yet relatively cold for a star.

The Power of the Australian SKA Pathfinder Telescope

The difficulty of detecting radio emissions in cooler stars such as WISE J0623 presents a challenge for radio astronomers. Enter the Australian SKA Pathfinder radio telescope, housed at the CSIRO Murchison Radio-astronomy Observatory, which has already surveyed almost 90% of the sky.

Differentiating millions of radio sources to identify radio stars involves detecting ‘circularly polarized radio emission’. By applying this strategy, WISE J0623 was discovered among the few known astronomical objects emitting significant circularly polarized light.

Decoding the Rhythms of WISE J0623

Follow-up observations revealed that WISE J0623 emitted two bright, circularly polarized bursts every 1.9 hours. This pattern of radio emissions, connected to the dwarf’s magnetic fields, mirrored its rotation rate.


WISE J0623, the coldest brown dwarf detected via radio waves, serves as a powerful tool for future research. Studies of such dwarfs will offer valuable insight into stellar evolution and the magnetic fields of giant exoplanets, bolstering our cosmic knowledge.

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Written by Ivan Petricevic

I've been writing passionately about ancient civilizations, history, alien life, and various other subjects for more than eight years. You may have seen me appear on Discovery Channel's What On Earth series, History Channel's Ancient Aliens, and Gaia's Ancient Civilizations among others.

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