Habitable Exoplanets May Have Earth-Like Magnetic Fields

A new research suggests that planets located outside our solar system also known as exoplanets have a high chance of being shielded by strong magnetic fields especially if they are located in the habitable zone.

The magnetic fields are crucial in protecting the planets from harmful radiation coming from both their star and other objects in the galaxy such as black holes. Scientists based their assumptions on computer models that helped them take a look at what may happen when an Earth-like exoplanet orbits a low mass M dwarf star, which is the most common type of star in the Milky Way.

The research team said that they assumed the planets were tidally bound to their stars and had a rate of rotation close to their orbital periods. Peter Driscoll, lead author of the study and planetary scientist the Carnegie Institution, said that exo-planets that are tidally locked closely to their host stars are more likely to be tidally heated.

Nevertheless, the team found that despite their tidal heat they could still have magnetic fields. Scientists explained that the higher the tidal heating is within the mantle the greater the chances of having a magnetic filed were on those planets.

Researchers also said that M dwarfs, which are sometimes half the mass of our sun, can help them detect Earth-like planets with great ease. That’s because closely tidally locked planets to their stars are very easy to detect when they are in transit.

But truly habitable planets are those that can both repel enough cosmic radiation to prevent the water from their surface to evaporate and are geologically active.

Researchers said that they previously believed that too much tidal heating would prevent a magnetic field from occurring. But computer models showed that those planets could still have an Earth-like magnetic field.

The team’s main concern was that tidal heating in the mantle would block the planets’ heat flow from their cores. This heat flow is the main trigger of magnetic fields, researchers suggest. But models showed that the planets can cool off real quickly at surface level.

Scientists argue that magnetic fields are crucial to habitability. Many die-offs and mass extinctions on Earth were caused by a disruption in the geomagnetic field. When that happens, solar radiation can reach lower elevations and compromise life.

As a follow-up, the team plans to measure radio emission frequencies around the exoplanets’ magnetic field. They will be able to do that by analyzing the high energy electrons that are supposed to ‘orbit’ around the planet’s magnetic fields.

Image Source: Flickr