Overview
- Researchers report in Astrophysical Journal Letters a 19‑day solar radio burst observed August 21 to September 9, 2025, setting a new duration record.
- Scientists kept near‑continuous watch by stitching data from Solar Orbiter, Parker Solar Probe, Wind, and STEREO‑A as the Sun’s rotation brought the source into view.
- The signal is a Type IV burst, which is radio emission from electrons trapped in the Sun’s magnetic fields in the corona.
- A new STEREO‑based method pinpointed the source to a helmet streamer, with three coronal mass ejections likely re‑energizing the trapped electrons to sustain the emission.
- The radio waves were harmless at Earth, yet the pattern offers forecasters a marker for regions that can fire off repeat eruptions that threaten satellites and astronauts.