NASA/ESA track 19-day Type IV solar radio burst

NASA said on May 14 that spacecraft from NASA and ESA tracked a Type IV solar radio burst that persisted for 19 days in 2025, far longer than scientists had previously recorded. The event began on Aug. 21, 2025, and remained visible through Sept. 9, according to NASA and the paper published in Astrophysical Journal Letters. The burst was observed by NASA’s STEREO, Parker Solar Probe and Wind missions, along with ESA and NASA’s Solar Orbiter. Researchers said the signal outlasted the previous record of five days. ### What exactly did scientists see for 19 days? The paper describes a hectometric Type IV continuum at roughly 0.5 to 3 megahertz that appeared in three successive viewing windows as the Sun rotated. NASA said each spacecraft saw the burst for only part of the full event because the source region moved into and out of view across the inner solar system. That multi-spacecraft geometry let researchers stitch together a single 19-day episode rather than separate shorter bursts. (science.nasa.gov) Type IV bursts are radio emissions produced by electrons trapped in magnetic structures associated with solar eruptions. NASA said these radio waves are themselves harmless, but the magnetic environments that produce them can also be associated with solar activity that sends energetic particles toward Earth and affects satellites and spacecraft. (science.nasa.gov) ### Why was this one different from other Type IV bursts? NASA said Type IV bursts usually last from hours to a few days. In this case, the event continued nearly three weeks, which the agency called record-breaking. A NASA catalog of decameter-hectometer Type IV bursts shows such events have historically been much shorter, and the new paper identifies this case as unprecedented in duration. (science.nasa.gov) The authors linked the long-lived emission to a corotating reservoir of electrons. The paper summary says the reservoir was likely sustained by multiple coronal mass ejections and-or continued injection from the low corona, an interpretation also reflected in NASA’s account of a trio of coronal mass ejections from the same region. ### Where did the burst come from on the Sun? (science.nasa.gov) NASA said researchers used a new technique based on STEREO data to trace the source to a helmet streamer, a large magnetic structure in the solar corona. Helmet streamers are the bright, V-shaped features often seen extending outward from the Sun during eclipses and in coronagraph images. NASA said scientists think three explosive outbursts in the same region may have fueled the event. (iopscience.iop.org) The paper’s title — “Unprecedented 19 Day Type IV Radio Burst as a Corotating Electron Reservoir” — reflects that source interpretation. The work was led by Vratislav Krupar and published in 2026 in Astrophysical Journal Letters, according to the journal listing cited by Phys.org and the DOI record. ### What about the reported “heartbeat” pulses? The May 21 social-media post cited 45-to-60-minute “heartbeat” pulsations within the burst. (science.nasa.gov) The research record available through the paper summary and NASA’s release confirms the 19-day duration, the spacecraft set and the corotating-electron-reservoir interpretation, but the pulse detail is not stated in NASA’s news post. Older NASA technical literature does describe pulsating Type IV bursts as a known phenomenon, with models tying pulsations to changes in magnetic fields and emission conditions. (phys.org) Because the paper itself is only partially accessible in the materials reviewed here, the 45-to-60-minute cadence should be treated as a detail from secondary discussion unless confirmed directly from the full journal text or author comments. The broader finding — a 19-day Type IV burst tracked across multiple spacecraft — is confirmed by NASA and the published paper record. (science.nasa.gov) ### Why were NASA and ESA both involved? ESA’s Solar Orbiter and NASA’s STEREO, Parker Solar Probe and Wind spacecraft were positioned at different points in the inner solar system during the event. NASA said that spread was essential because the Sun’s rotation carried the source into view of different instruments over time. ESA has separately highlighted Solar Orbiter’s Radio and Plasma Waves instrument as a tool for detecting solar radio bursts. (science.nasa.gov) Astrophysical Journal Letters now hosts the formal report, and NASA’s May 14 science post remains the agency’s public summary of the event. Researchers identified the burst as running from Aug. 21 to Sept. 9, 2025, using coordinated observations from STEREO, Parker Solar Probe, Wind and Solar Orbiter. (science.nasa.gov)