So far, astronomers have confirmed over 6,300 exoplanets circling a host star beyond our solar system. They range from small, rocky worlds to enormous orbs of gas like our own Jupiter or Saturn. Some, scientists suspect, could host life because they orbit their star in the habitable zone, the region where conditions are just right for liquid water to exist on their surface.
Getting a close glimpse of these worlds remains challenging because of the unfathomable distances involved. Distinguishing the signals emanating from these exoplanets from their far brighter host stars has also been an insurmountable challenge — until now.
As detailed in a yet-to-be-peer-reviewed paper, a team of astrophysicists from Harvard and the University of Oregon, Eugene, say they’ve detected radio signals directly from an exoplanet for the first time using the MeerKAT radio telescope in South Africa.
The planet, dubbed beta Pictoris b, is a gas giant with a mass of over 11 Jupiters that takes over 23 Earth years to orbit its host star. It was first discovered in 2008 and is located 64 light-years from Earth.
And no, it’s not a sign that an extraterrestrial civilization somehow living on the gas giant is trying to contact us. The radio emissions appear to be the result of naturally occurring auroras, charged particles moving along the planet’s magnetic field, not unlike the ones we experience here on Earth.
“We detect rapid, recurring, and highly circularly polarized bursts, as well as persistent emission, at frequencies of 0.85 to 3.5 GHz,” the researchers note in their paper.
The team managed to isolate the signal from the exoplanet’s host star, beta Pictoris, by using the known location of quasars to determine the exact source location. Quasars are extremely magnetized and bright celestial objects at the centers of galaxies that are powered by supermassive black holes. Astronomers use them as “lighthouses” to triangulate the location of other distant objects.
The direct radio emission detection even allowed the team to determine that the exoplanet’s magnetic field is over 300 times as strong as that of Jupiter’s.
“This constitutes the first direct measurement of magnetic field strength for an exoplanet, and is consistent with dynamo-scaling predictions for a young, massive giant planet,” the researchers noted in their paper.
While we’re now able to analyze their radio wave emissions, visiting these distant worlds remains a distant dream. Even the furthest human-made spacecraft, Voyager 1, is only slowly approaching a distance of a single light-day away from Earth — while the closest star system, Proxima Centauri, which is believed to be home to a “super-Earth” exoplanet, is over four light-years away.
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