NASA’s newest sun-watcher, the Interface Region Imaging Spectrograph, launched in 2013 with a specific goal: track how energy and heat coursed through a little understood region of the sun called the interface region. Sandwiched between the solar surface and its outer atmosphere, the corona, the interface region is where the cooler temperatures of the sun’s surface transition to the hotter temperatures above. Moreover, all the energy to power the sun’s output — including eruptions such as solar flares and the sun’s constant outflow of particles called the solar wind — must make its way through this region.
Five papers based on IRIS data will highlight different aspects of the energy’s journey from the sun’s surface through its atmosphere in the Oct. 17, 2014, issue of Science magazine. By looking at various regions of the interface region in unprecedented resolution, the papers offer clues to what heats the corona to unexplained temperatures of millions of degrees, far hotter than the surface of the sun itself, as well as what causes great writhing movement and accelerated particles throughout the solar atmosphere.
“This set of research really delivers on the promise of IRIS, which has been looking at a region of the sun with a level of detail that has never been done before,” said Bart De Pontieu the IRIS science lead at Lockheed Martin in Palo Alto, California. “The results focus on a lot of things that have been puzzling for a long time and they also offer some complete surprises.”
Solar Heat Bombs
One of the biggest surprises comes in the form of heat pockets of 200,000 F, low in the solar atmosphere – far lower down than where such high temperatures were expected. In a paper led by Hardi Peter of the Max Planck Institute for Solar System Research in Gottingen, Germany, the pockets were named bombs because of how much energy they release in such a short time.
Bright lights in this movie from NASA’s IRIS, represents spots of intense heat — at 200,000 F — that may hold clues to what heats the solar atmosphere to mysteriously high temperatures.
Image Credit: NASA/IRIS/Peter
Identifying different temperature material in the solar atmosphere is fairly straightforward, but it is much more complex to determine how high above the surface such material lies. Spotting such features relied heavily on IRIS’ high-resolution spectrograph, an instrument that divides incoming light into its separate wavelengths. Such spectra can then be analyzed to see what temperature material is present in a given area as well as how dense it is and how fast it is moving. IRIS showed this very hot material sandwiched between two cold layers at temperatures usually found only near the sun’s surface, thus giving information about its low-lying location that would have been otherwise hard to find…. Continue reading NASA’s IRIS Helps Explain Mysterious Heating of the Solar Atmosphere