By studying the behavior of iron under the extreme pressure and temperature conditions that prevail in the cores of super-Earth type exoplanets, a team of American researchers has shown that their magnetic fields, serving as a shield against cosmic radiation , are much more common and long-lasting than previously thought.
It was using one of the most powerful lasers on the planet that researchers at the Lawrence Livermore National Laboratory in the United States came to this conclusion. By placing a sample ofunder extremely high pressure conditions – 1,000 gigapascals (GPa), i.e. three times the pressure prevailing in the Earth’s inner core -, then by exposing it to laser radiation to heat it, they were able to determine the point of iron. The temperature at which iron melts under such pressure conditions is a key parameter in defining the size and nature of the inner nuclei Earth-like planets.
Liquid iron to generate a shield against cosmic radiation
The existence of a liquid nucleus is an important argument to determine the presence of aaround a planet: on Earth, the magnetic field is generated thanks to the movements of in the outer liquid core, surrounding the . This magnetic field protects us, among other things, from cosmic radiation, which is highly harmful to living organisms; the presence of a is thus considered necessary for the habitability of a planet.
According to their study, the researchers showed that a liquid metallic core would last longer in the case of a planet four to six times more massive than Earth, suggesting that exoplanets of the typewould be likely to be equipped with a more durable magnetic protection than that of our Planet, protecting them more effectively from .