First ever magnetic field detected from an exoplanet

The exoplanet, HAT-P-11b, was found using the Hubble Space Telescope (HST) data.

Astronomers have identified and confirmed 4,884 planets outside our solar system, with another 8,288 potential candidates. However, no magnetic fields around any of these exoplanets had been detected until now. A team of astronomers from NASA's Jet Propulsion Laboratory (JPL), the European Space Astronomy Centre (ESAC), and many other institutes and universities published their findings in a new paper in Nature Astronomy.

The team observed HAT-P-11b, an exoplanet roughly the size of Neptune that orbits a K-type (orange dwarf) star found 123 light-years away from Earth, designated HAT-P-11. They found it using a technique known as Transit Spectroscopy, or the Transit Method, where the decrease in the brightness of a star periodically indicates a planet passing in front of it. It is used to detect exoplanets and reveal details about their atmospheres.

Hubble observed HAT-P-11b making six transits around the HAT-P-11 star while observing it in the ultraviolet spectrum. It also detected carbon ions in the atmosphere, for which the team believes the most likely explanation is the existence of a magnetosphere.

"This is the first time the signature of an exoplanet's magnetic field has been directly detected on a planet outside our solar system. A strong magnetic field on a planet like Earth can protect its atmosphere and surface from direct bombardment of the energetic particles that make up the solar wind. These processes heavily affect the evolution of life on a planet like Earth because the magnetic field shelters organisms from these energetic particles," said Gilda Ballester, a co-author for the paper.

You can read more from the paper here.