Balloon-Borne Sunrise-III Observatory Reveals Twisted Magnetic Threads in the Sun's Atmosphere

Key facts

• An international team led by the National Astronomical Observatory of Japan detected thin, thread-like magnetic structures in the Sun's chromosphere using Sunrise-III, a balloon-borne solar observatory that flew a one-meter telescope about 35 kilometers above Earth during a July 2024 mission lasting roughly six and a half days.
• Some of the detected magnetic threads, typically narrower than one arcsecond, had polarities opposite to the surrounding magnetic canopy, with line-of-sight field strengths around 10 to 20 gauss weaker than the surrounding canopy.
• The findings, published in The Astrophysical Journal Letters and highlighted by ScienceDaily on October 24, 2026, were made above quiet-Sun regions without prominent sunspots, which cover most of the solar surface.
• The Sun's photosphere is about 5,500 degrees Celsius while the corona above reaches millions of degrees, a temperature increase that has puzzled scientists for decades.
• Numerical simulations suggest surface motions twist magnetic field lines into rope-like formations, where magnetic reconnection could convert magnetic energy into heat, though the study did not establish that these threads heat the corona.
• The Sunrise Chromospheric Infrared spectroPolarimeter (SCIP), developed under Japanese leadership, measured magnetic fields using polarized infrared light across a region of about 58 by 58 arcseconds.
• Sunrise-III also mapped magnetic fields along spicules, narrow jets of solar material extending thousands of kilometers above the visible surface.