Although all gas giants outside the solar system are uninhabitable, the presence of a magnetic field may be one of the factors that helped make a rocky planet, such as , habitable.
These exoplanets each orbit very close to a large, hot star, so that one side of them is always facing the star, and the other side is always far away, just like the Moon and Earth.
This type of planet is called a “hot Jupiter” because its size and composition are similar to the largest planet in our solar system, although its temperature is much higher. The mass of the seven planets ranged from about the same as the mass of to more than three times that.
The bright and dark sides
Strong winds blow from the hot “light side” to the cold “dark side” on these planets, due to their orbits being close to their stars, which makes their atmosphere extremely hot on the light side. All of them are closer to their host star than Mercury, the closest planet in the solar system, is to the sun.
“What you might expect is that the winds would be stronger on planets with higher temperatures, so the more energy you put into the system, the stronger the winds should be,” said Julia Seidel, an astronomer at the Lagrange Laboratory of the Côte d’ Observatory in Nice, France, and the lead researcher on the study. “But we are seeing the opposite.”
She added that “hotter planets are less susceptible to strong winds affecting their atmosphere, which is really strange compared to what we know about the nature of atmospheres.”
She continued: “This means that all that energy that the star pumps into the planet’s atmosphere must be dissipated in a different way, and the only possibility for slowing the atmosphere’s movement at this speed is through the magnetic field, and its interaction with the charged particles moving in .”
Wind speeds on the seven exoplanets reach 25,000 kilometers per hour, stronger than those on Jupiter.
Given that most planets in the solar system have magnetic fields, researchers believe it is not surprising that exoplanets also have magnetic fields, but they noted that scientists have so far found it difficult to come up with convincing evidence.
