With the most powerful radio antenna on Earth, researchers from the University of Queensland have detected radio signals from distant stars.
Dr. Benjamin Pope of the University of Queensland and colleagues from the Dutch national observatory ASTRON have been using the Low-Frequency Array (LOFAR) in the Netherlands to observe radio waves emanating from distant stars. These waves suggest the existence of unknown planets orbiting these stars.
"We've discovered signals from 19 distant red dwarf stars, four of which are best explained by the existence of planets orbiting them. We've long known that the planets of our own solar system emit powerful radio waves as their magnetic fields interact with the solar wind, but radio signals from planets outside our solar system had yet to be picked up. This discovery is an important step for radio astronomy and could potentially lead to the discovery of planets throughout the galaxy," said Dr. Pope.
Previously, only the nearest stars were detectable by astronomers from their steady radio wave emission. Now, radio emissions can be observed coming from regular stars elsewhere, aiding the search for planets nearby. The research team focused on red dwarf stars, which have intense magnetic activity driving stellar flares and radio wave emission. They observed radio emissions from magnetically inactive stars, and they concluded the signals were coming from magnetic connections between the stars and unseen orbiting planets.
"We can't be 100 percent sure that the four stars we think have planets are indeed planet hosts, but we can say that a planet-star interaction is the best explanation for what we're seeing," Dr. Pope said.
LOFAR can only monitor stars up to 165 light-years away. However, with Australian and South African governments constructing the Square Kilometre Array radio telescope, estimated to start operating in 2029, the future of radio astronomy is bright.