The breakthrough could lead to a better understanding of habitable planets
Using the Dutch-led Low Frequency Array (LOFAR) radio telescope, located mainly in Dwingeloo (Drenthe), astronomers at the Dutch institute for astronomy (ASTRON) have discovered unusual radio waves coming from the nearby red dwarf star GJ1151.
The radio waves bear the tell-tale signature of aurorae caused by an interaction between a star and its planet. The radio emissions from a star-planet interaction like this was over thirty-years ago, but this is the first time astronomers have been able to discern its signature.
This method is only possible with a sensitive radio telescope like LOFAR, and opens the door to a new way of discovering exoplanets in the habitable zone and studying the environment they exist in.
Red dwarfs are the most abundant type of star in our Milky Way, but much smaller and cooler than our own Sun. This means that for a planet to be habitable, it has to be significantly closer to its star than the Earth is to the Sun. Red dwarfs also have much stronger magnetic fields than the Sun, which means, a habitable planet around a red dwarf is exposed to intense magnetic activity. This can heat the planet and even erode its atmosphere. The radio emissions associated with this process are one of the few tools available to gauge this effect.
“The motion of the planet through a red dwarf’s strong magnetic field acts like an electric engine much in the same way a bicycle dynamo works. This generates a huge current that powers aurorae and radio emission on the star.” says Dr Harish Vedantham, the lead author of the study and a Netherlands Institute for Radio Astronomy (ASTRON) staff scientist.
“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.
Images via ASTRON
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