Solar Orbiter, a Sun-observing probe, has been providing unprecedented close-up views of the Sun’s polar regions for nearly five years. During recent flybys, it captured images of tiny, hair-like jets near the Sun’s south pole, revealing a surprising source of both fast and slow solar wind.
This discovery, published in Astronomy and Astrophysics, builds upon initial observations made by the European Space Agency’s (ESA) Solar Orbiter in 2023. These brief, flashing jets, lasting approximately one minute, expel charged particles at speeds of around 62 miles per second (100 kilometers per second).
Solar wind, a stream of charged particles emanating from the Sun’s corona (its outermost atmospheric layer), permeates the solar system. While the origin of fast solar wind from coronal holes—areas where the Sun’s magnetic field extends outward—has been understood for decades, the source of slow solar wind remained a mystery.
Researchers combined Solar Orbiter’s high-resolution images with measurements of solar wind particles and the Sun’s magnetic field, tracing the solar wind back to these miniature jets. Astonishingly, both fast and slow solar wind appeared to originate from these same jets. This unexpected finding challenges previous assumptions about the distinct origins of these two forms of solar wind.
The discovery was made possible by Solar Orbiter’s close proximity to the Sun, orbiting at roughly one-quarter the distance between Earth and the Sun. This unique vantage point allows for detailed observations of solar phenomena. With two close solar approaches each year, researchers anticipate gathering more data during future flybys to further understand these jets and their role in generating solar wind.
This breakthrough in understanding solar wind generation has significant implications for space weather forecasting and our understanding of the Sun’s influence on the solar system. Further observations from Solar Orbiter promise to unveil even more details about these dynamic solar jets and their crucial role in shaping our space environment.
