Astronomers Have Detected a Planet’s Radio Emissions 51 Light-Years Away

Astronomers have detected thousands of exoplanets, but there’s only so much we can know about them from light-years away. A new study from Cornell University could help shed light on the conditions of exoplanets by analyzing radio emissions connected to their magnetic fields. The researchers claim this marks the first time an exoplanet has been detected in the radio bands. 

This project started with the study of Jupiter, which has a hugely powerful magnetic field. Several years ago, study lead author Jake Turner conducted an analysis of Jupiter’s magnetic field. In the new study, that data becomes the basis for hunting exoplanets. The team processed the Jupiter data to simulate the radio frequency signal from a distant gas giant. 

The results became a template for similar planets that might be 40 to 100 light-years away from the observer. Using the Low Frequency Array (LOFAR), the team scanned several nearby solar systems that are known to host exoplanets. If the signals from one of these stars matched the template, that would indicate they’d found an exoplanet’s emissions in the radio spectrum. 

It took more than 100 hours of observational time, but a star known as Tau Boötes 51 light-years distant exhibited exactly the kind of signal the researchers were hoping to find. Turner and his colleagues even used other radio telescopes to repeat the analysis, and the signal is still there. And that makes sense — Tau Boötes has one known exoplanet, a gas giant called Tau Boötes b that orbits very close to the star. 

According to the researchers, the signal is understandably very weak. There were several other stars with radio pings that could have been planets, but the one in Tau Boötes was much more significant. The team is now calling on other researchers to confirm the findings — data on an exoplanet’s magnetic field could be invaluable, but it’s still possible the signal is coming from the star or some other local source rather than the planet. 

The researchers say that the magnetic field of a planet can offer hints of composition and habitability. For example, Earth’s magnetic field is a product of the planet’s iron core, and the field helps deflect dangerous radiation that can harm living things and strip away a planet’s atmosphere. Mars’ lack of a magnetic field is believed to be one of the reasons it’s so inhospitable. After confirming and refining Turner’s results, astronomers might be able to learn about distant worlds by scanning for radio frequency emissions.

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