Thanks to the Sun's weak magnetic field and the larger distance to the planets, similar currents are not generated in the solar system. However, the interaction of Jupiter’s moon Io with Jupiter’s magnetic field generates a similarly bright radio emission, even outshining the Sun at sufficiently low frequencies.

"We adapted the knowledge from decades of radio observations of Jupiter to the case of this star" said Dr Joe Callingham, ASTRON postdoctoral fellow and co-author of the study. “A scaled up version of Jupiter-Io has long been predicted to exist in the form of a star-planet system, and the emission we observed fits the theory very well.”

Video showing the science behind the discovery

The group is now concentrating on finding similar emission from other stars. “We now know that nearly every red-dwarf hosts terrestrial planets, so there must be other stars showing similar emission. We want to know how this impacts our search for another Earth around another star” says Dr Callingham.

The team is using images from the ongoing survey of the northern sky called the LOFAR Two Metre Sky Survey (LoTSS) of which Dr Tim Shimwell, ASTRON staff scientist and a co-author of the study, is the principal scientist. “With LOFAR’s sensitivity, we expect to find around 100 of such systems in the solar neighborhood. LOFAR will be the best game in town for such science until the Square Kilometre Array comes online.” says Dr Shimwell.

The group expects this new method of detecting exoplanets will open up a new way of understanding the environment of exoplanets. “The long-term aim is to determine what impact the star’s magnetic activity has on an exoplanet’s habitability, and radio emissions are a big piece of that puzzle.” said Dr Vedantham. “Our work has shown that this is viable with the new generation of radio telescopes, and put us on an exciting path.”

Paper link

'Coherent radio emission from a quiescent red dwarf indicative of star–planet interaction' is published in Nature Astronomy on 17 February 2020: https://www.nature.com/articles/s41550-020-1011-9

DOI: https://doi.org/10.1038/s41550-020-1011-9