A new way to study the Universe outside the Solar System has proven to be rewarding. With the help of the Low-Frequency Array, a radio telescope in the Netherlands, and the High Accuracy Radial Velocity Planet Searcher on the Italian Telescopio Nazionale Galileo in Spain, astronomers detected distinct signatures of aurorae there.
An aurora is sometimes referred to as polar lights. They are also known as aurora borealis (northern lights) or aurora australis (southern lights). It is a natural light display in the Earth’s sky, predominantly seen in the high-latitude regions around the Arctic and Antarctic. But it looks like we are not the only place in the Universe that displays aurorae.
They are the result of disturbances in the magnetosphere caused by the solar wind. These disturbances are sometimes strong enough to alter the trajectories of charged particles in both solar wind and magnetospheric plasma. These particles precipitate into the upper atmosphere. The resulting ionization and excitation of atmospheric constituents emit light of varying color and complexity. This is what we see when we watch the breathtaking astronomic event.
Auroras on exoplanets help scientists study distant worlds
After analyzing different possibilities as of what binary system could generate the magnetic field that made the Low-Frequency Array register radio emissions, the scientist concluded that it has to be an interaction between a star’s magnetic field and a planet that in orbits it. A red dwarf that hosts a terrestrial planet is sending radio emissions to Earth.
Until now, radio emissions from another planet were just a presumption, but now astronomers are optimistic that this will be the way to understand the habitat of exoplanets. There are several means to get there, but determining the impact of the star’s magnetic activity on an exoplanet’s habitability is one of the most important ones.
“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 Joe Callingham, ASTRON postdoctoral fellow and co-author of the Nature Astronomy paper.