A team of scientists at Cornell University has detected what they believe to be the first radio emission in history to be seen outside our solar system. We hasten to clarify: this does not mean that the signal was sent by aliens.
When a stellar wind – a stream of charged particles from a star – enters the magnetic field of a planet, changes in its speed can be recorded in the form of changes in radio emission from this planet. For astronomers, observations of planetary radio emission provide valuable information about its internal structure, the state of its atmosphere, and its general suitability for life.
Several years ago, scientists at Cornell University launched the BOREALIS program to observe radio emissions from distant exoplanets. They recently decided to use the LOFAR telescope in the Netherlands to take a closer look at three systems that contain known exoplanets: 55 Cancer, Epsilon Andromeda and Tau Bootes.
And only in Tau Bootes, located 51 light-years from us, they discovered the planetary radio emission that they were looking for. If the data are confirmed, it will be possible to say the following: the electromagnetic field on the surface of this distant planet has a strength of 5 to 11 Gauss (for comparison, the induction of the magnetic field on the surface of the Earth is approximately 0.25-0.6 Gauss). These parameters indicate that the exoplanet’s core is composed of metallic hydrogen.
The presence of a strong magnetic field in Earth-like exoplanets is of great importance, since it protects them from stellar wind and cosmic radiation and provides a chance for the birth of life (or simply makes them habitable). The signal seen by scientists at Cornell University is very weak and needs confirmation by other telescopes before astronomers can confirm its nature.
Now scientists do not exclude that stellar flares are the source of radiation, but if the planetary origin of the signal is confirmed, this will mean that Tau Bootes, most likely, is suitable for life planet.