Like meteorologists give first names to tropical cyclones, solar events (especially strong ones) are also named — but they’re given names based on their dates. Also like cyclones, some solar storms are more famous than others.
The Halloween Storms of 2003, for instance, are among these famous ones. They created auroras at lower latitudes than expected. On March 8, 2019, a peculiar solar storm formed; it was named the 2019 International Women’s Day event. Now, a team has found even more weird things about the storm.
Space weather events are famous for the impressive amount of energy released in the solar system. Coronal Mass Ejections (CME) happen when the Sun releases plasma from a strong magnetic field. Some CMEs are associated with solar flares which are solar activities connected to the 11-year solar cycle.
During solar maximums, more solar flares occur — and since they can trigger geomagnetic storms that can disable satellites and knock out electric power grids, researchers are following them closely. This one was unusual from the start.
“This solar storm seemed peculiar from the very first moment. It had many accompanying phenomena that could be observed at the Sun, something that is usual for very strong solar storms. The only trouble was — the storm was not strong at all!”
says Dr. Mateja Dumbović, the lead author of the study and a research associate at Hvar Observatory in Croatia.
Solar flares are rated from weak to strong (A, B, C, M, and X). The X-class flares, the strongest of the bunch, are powerful enough to power 1.2 billion Saturn V rockets — enough energy to explore the entire solar system. In the 2019 event, the storm was C-class, not extremely strong. However, solar activity that usually comes with stronger flares was observed.
After the flare, two Extreme Ultraviolet (EUV) waves were registered during the event. These are dangerous phenomena which can weaken the Earth’s magnetic field. As the Sun was emitting all that energy, a ‘hole’ of power is left behind, it is called a coronal dimming.
In the International Women’s Day event, type II and III radio bursts were present. Radioactivity is the usual concern with space weather because of potential interference with satellites, especially those related to georeference. Every time a strong CME is happening, intense radio emissions can be detected, this is called radio burst.
Usually, unlike the International Women’s Day event, space weather can bring us beautiful auroras, but life is not a bed of roses. Events like this are rare, but when they occur they can cause serious problems for us.
The study was published in Astronomy & Astrophysics.