Strange winds on seven hot Jupiters reveal strongest signs yet of exoplanet magnetic activity
Baku, June 2, AZERTAC
A team of astronomers has found the strongest evidence yet that some planets outside our solar system may be magnetic. Using the European Southern Observatory's Very Large Telescope (ESO's VLT) and the Gemini North telescope, the researchers measured wind speeds on seven very hot, Jupiter-like exoplanets, according to PhysOrg.
The observations reveal that the winds on these planets are most likely governed by magnetic fields, providing the first robust measurement of magnetism on planets outside the solar system.
"This breakthrough opens a completely new window on exoplanet research. It's the first time we can compare the magnetic environments of other worlds—a key step toward ultimately understanding which planets can stay alive, keep their water, and perhaps even, one day, host life as we know it," says Julia Seidel, an astronomer at the Laboratoire Lagrange, Observatoire de la Côte d'Azur, France and lead author of the study published in Nature Astronomy.
Earth's magnetic field influences our atmosphere in complex ways, and is therefore a key factor in understanding what keeps the planet habitable for life. Magnetic fields are also present in other solar system planets, like Jupiter and Saturn. However, for the past 15 years, no one succeeded in directly measuring the strength of the magnetic fields of exoplanets—until now.
The team, however, didn't set out to measure magnetic fields but, rather, winds. They measured wind speeds on seven exoplanets orbiting different stars: gas giants like Jupiter, but each tidally locked to its host star and very close to it.
Just as we always see only one side of the moon, these planets always keep one face towards the star, resulting in a scorching hot day side and a freezing cold night.
This temperature difference creates a climate completely different from the one on our planet, with extremely strong winds. The wind speeds in their sample ranged from around 7,200 km/h to over 25,000 km/h; in comparison, the fastest winds measured on Jupiter reach speeds of around 1,500 km/h.
"In the beginning, we set out to check if the atmospheric winds behaved the same way for all hot planets," explains Seidel, who was previously an astronomer at ESO in Chile.
For their measurements, the team used data from the ESPRESSO instrument on ESO's VLT, in the Chilean Atacama Desert, and from a similar instrument on the Gemini North telescope in Hawaiʻi, U.S. (The VLT is an ESO telescope while Gemini North is one half of the International Gemini Observatory, operated by NSF NOIRLab.)
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