In a dramatic multi-stage eruption, the Sun has uncovered new clues that could help scientists unravel the long-standing mystery of the causes of the Sun’s powerful and unpredictable eruptions. Discovering this fundamental physics can help scientists better predict the eruptions that cause dangerous cosmic weather conditions on Earth.
This explosion contains components of three different types of solar flares, which usually occur separately – making the first announcement of such an event. The presence of all three types of eruptions together in one event provides scientists with something like a Rosetta sunstone, which allows them to translate their knowledge of each type of solar eruption to understand other types and discover a basic mechanism that could explain all types of solar flares.
“This event is a missing link where we can see all these aspects of the different types of eruptions in one clean little package,” said Emily Mason, lead author of the new study and solar scientist at NASAGoddard Space Flight Center in Greenbelt, Maryland. “This leads to the fact that these eruptions are caused by the same mechanism, only on a different scale.”
Sun eruptions usually come in one of three forms: coronal mass ejection, jet ejection, or partial eruption. Coronal mass ejections – CME and jets are both explosive eruptions that throw energy and particles into space, but look very different. As the jets erupt like narrow columns of solar material, CMEs form huge bubbles that expand, push out, and sculpt from the Sun’s magnetic fields. Partial eruptions, on the other hand, begin to erupt from the surface, but do not cause enough energy to leave the Sun, so most of the material falls back onto the solar surface.
In this eruption – observed by NASA’s Solar Dynamics Observatory and the European Space Agency and NASA’s Solar and Heliosphere Observatory on March 12 and 13, 2016 – scientists saw the release of a hot layer of solar material over a magnetically active region on the Sun’s surface. The discharge was too large to be jet, but too narrow to be CME. Within half an hour a second cool layer of material on the surface also began to erupt from the same spot, but eventually it fell back as a partial eruption. Seeing eruptions with both reactive and CME characteristics tells scientists that they are probably caused by a single mechanism.
An unusual eruption of the Sun may offer clues to understanding our star’s mysterious explosions. The new study examines an event called the “Rosetta Stone” of solar flares. Just as the Rosetta Stone is the key to understanding Egyptian hieroglyphs, studying this eruption can be the key to understanding all kinds of solar eruptions. Credit: NASA / Mara Johnson-Gro / Hailey Reed
With this new understanding, scientists can apply what they know about jets to CME. The event also tells scientists that partial eruptions occur in the same spectrum, but encounter some as yet unknown limiter that limits their energy and prevents them from escaping the Sun.
Understanding the mechanism behind these events, especially CME, is crucial in predicting when a major eruption could cause disturbances on Earth. In particular, CMEs release large clouds of high-energy charged particles and magnetic fields that leak out through the solar system and can lead to space time – a storm of high-energy particles and activity that can be dangerous to astronauts and technology in space and, in extreme case, useful networks on Earth.
By modeling the new eruption of Rosetta and others, once discovered like it, scientists hope they can understand what root mechanism causes solar flares and determine their characteristics. Finding a trigger could ultimately allow scientists to predict when a major eruption could threaten Earth and Mars a few hours in advance – providing enough time for astronauts and spacecraft operators to take precautions.
The new study was presented on June 7, 2021 by Mason at the AAS 238 meeting and was accepted for publication in Astrophysical Journal Letters.