For many years, it was almost impossible for scientists to study the sun's corona, but new research has just confirmed the unexplored energy that is responsible for its hot temperature.
What Did They Discover About The Corona?
A team of astrophysicists recently discovered the physical factors that result in the heating of the corona of the sun to 1 million degrees Fahrenheit or higher. The corona is the plasma that surrounds the Sun.
The findings were published in the Astrophysical Journal.
"We knew that something really intriguing happens at the interface between the photosphere — the sun's surface — and the corona, given the noticeable disparities in the chemical composition between the two layers and the sharp rise in plasma temperatures at this junction," said Gregory Fleishman, a professor at the New Jersey Institute of Technology and lead author of the study.
The researchers tracked regions in the corona of the sun from NASA's Solar Dynamics Observatory. They noticed higher heavy metal ions within magnetic flux tubes that have an electrical current.
How Did They Discover The Corona's Temperature?
The sun's corona is largely invisible to the human eye in most circumstances. Scientists have long known that the corona, as well as other regions on the sun, is hotter than the actual star. However, without properly studying it, they were unable to determine what is behind this phenomenon.
While studying the observations of the corona, the researchers captured vivid images. The photos were taken in the extreme (short wave) ultraviolet (EUV band). The researchers revealed massive concentrations of multiple charged metals in the corona, the outermost layer. The photosphere, which is the deepest layer of the sun that is noticeable, has single-electron ions of hydrogen. This presented an imbalance that explains the temperature differences.
What Does This Discovery Mean?
The researchers said that their accomplishment is "one of the greatest challenges for solar modeling."
"These observations suggest that the corona may contain even more thermal energy than is directly observed in the EUV range and that we have not yet accounted for," said Fleishman.
The researchers plan to combine their data with the findings from other scientists to clear up any differences in the energy that has been discovered.
Iron particles were also discovered in "ion traps" within the corona. This new discovery could possibly explain why previous scientists were unable to detect the energy in the EUV range.