Astronomers have discovered an unexpected mysterious signal from four dwarf stars 160 million light-years away from the solar system. According to signal analysis, the activity is evidence of the existence of an unseen exoplanet.
Astronomers confirmed that the signal did not come from an alien civilization outside the planet, but rather the result of interactions between the exoplanet and the star's magnetic field. This interaction produces a very strong aurora that can be detected using the Low Frequency Array (LOFAR), a powerful radio telescope in the Netherlands.
"We have found signals from 19 far red dwarfs, four of which are best explained by the presence of planets orbiting them," said physicist Benjamin Pope of the University of Queensland in Australia.
Astronomers have long known that the planets in our Solar System emit powerful radio waves when their magnetic fields interact with the solar wind.
But radio signals from planets outside our Solar System have never been detected. This discovery is an important step for radio astronomy and has the potential to lead to the discovery of planets throughout the galaxy.
It is thought that planets orbiting near red dwarfs might produce emissions similar to but more intense than those produced by Jupiter and Io, producing auroras at the stellar poles.
The first red dwarf radio emission consistent with this type of interaction was found in a red dwarf star last year. Now scientists have created a larger net to produce three new stars.
"Our model for radio emission from our stars is an improved version of Jupiter and Io," said astronomer Joseph Callingham of the Dutch Institute of Radio Astronomy (ASTRON), who led the study.
So far the team has not found any signs of exoplanets hinted at by the new method, apart from radio emission. But if the exoplanet is there, future observations using the radial velocity method could help reveal it.
"We're not yet 100 percent sure that the four stars we think have planets are indeed planetary hosts," Pope said.
Pope believes the best explanation for the mysterious signal is a planet or star interaction. "Further observations are continuing but we are ruling out planets that are more massive than Earth," he said.