Radio signals detected coming directly from exoplanet for first time

Radio signals have been detected from a gas giant exoplanet around 64 light-years from Earth by South Africa’s MeerKAT radio telescope.

First discovered in the 1990s, exoplanets, or worlds orbiting stars outside of our solar system, have long proven difficult to discern as to the origin of radio signals, or if the signals originate from their associated stars.

However, a team of scientists led by Kevin Ortiz Ceballos at the Center for Astrophysics, Harvard & Smithsonian, detected radio signals coming directly from auroras linked to the powerful magnetic field of a planet called β Pictoris b.

Although sadly not a sign of alien life, the radio waves are an exciting development in understanding the magnetic fields and theories about exoplanet interiors.

Revealing more about the interiors of exoplanets

Using the radio signals, the researchers were able to calculate that β Pictoris b has a magnetic field strength of at least 1,250 gauss where the radio waves are produced. That is far stronger than Jupiter’s magnetic field: “This constitutes the first direct measurement of magnetic field strength for an exoplanet.”

In their paper, the authors state that their result matches theoretical predictions for the strength of the magnetic fields generated by young, massive giant planets.

The discovery also gives scientists a new way to directly measure an exoplanet’s magnetic field and test theoretical models of planetary interiors.

The team used quasar images to contextualise the mysterious signals

When the faint, repeating bursts of radio signals were first detected, the team were unsure if they were originating for the star or planets of the β Pictoris system. To pinpoint the source, the researchers compared their radio images with precise positions of extremely distant background quasars, which acted as fixed markers.

Using the quasars positions, the team were able to plot the exact positions of both the star and the planet. When they layered their radio images over that map, the radio signal lined up with the position of β Pictoris b rather than its parent star.

“Here, we report the first direct detection of auroral radio emission from an exoplanet, the giant planet β Pictoris b, with the MeerKAT array,” wrote the team in a paper posted to the arXiv preprint server.