New research suggests Earth-like planets orbiting close to relatively small stars most likely have protective magnetic fields that could make them hospitable to life.
The magnetic fields could deflect charged particles from solar winds, prevent the planet's atmosphere from escaping into space, and protect living beings from solar radiation, the University of Washington reported.
Low mass stars are the most common in the universe, and planets can orbit much closer to these types of stars while remaining in the habitable zone than we can to the Sun. Planets that are extremely close to their host star become tidally locked, with one side permanently facing forward. This phenomenon creates tidally generated heat inside the planet, also known as "tidal heating," and drives volcanic activity.
"The question I wanted to ask is, around these small stars, where people are going to look for planets, are these planets going to be roasted by gravitational tides?" Said lead author Peter Driscoll.
To answer that question, the researchers combined models of orbital interactions and heating with those of thermal evolution of planetary interiors. It has been generally believed that tidally locked planets lack magnetic fields, but the new research suggests tidal locking could actually help drive a magnetic field. When a planetary mantle is tidally heated it becomes better at dissipating its heat, this phenomenon causes the core to cool down and the magnetic field to appear. The computer simulations were able to generate magnetic fields for planets orbiting close to their host stars, including those near low-mass stars where life could potentially exist.
"These preliminary results are promising, but we still don't know how they would change for a planet like Venus, where slow planetary cooling is already hindering magnetic field generation," Driscoll said. "In the future, exoplanetary magnetic fields could be observable, so we expect there to be a growing interest in this field going forward."
The findings were published in a recent edition of the journal Astrobiology and was done through the Virtual Planetary Laboratory.
