According to a news release from NASA’s Goddard Space Flight Center, the region positioned between the surface of the solar furnace and its atmosphere has been shown to be a much more violent place than previously thought. This was the conclusion reached by astronomers after examining photos and data provided by the space agency’s Interface Region Imaging Spectrograph (IRIS).
IRIS examines the sun in layers. By capturing light given off by atoms of various temperatures, IRIS can concentrate on various heights above the sun’s surface extending well out into the solar atmosphere, known as the corona. IRIS was designed to examine the interface region — a layer between the giant fireball’s surface and corona that previously was not well known.
“The quality of images and spectra we are receiving from IRIS is amazing,” noted Alan Title, IRIS principal investigator at Lockheed Martin, in a statement. “And we’re getting this kind of quality from a smaller, less expensive mission, which took only 44 months to build.”
IRIS is allowing astronomers to examine the explosive phenomena in the interface region in enough detail to figure out their role in heating the outer solar atmosphere.
IRIS obtains both photos and what’s known as spectra, which show how much of any given wavelength of light is present. This matches how much material in the solar atmosphere is present at specific velocities, temperatures and densities. The combined photos and spectra have offered new imagery of a region that was thought to be dynamic, but reveals it to be even more violent and unsettled that perceived.
“We are seeing rich and unprecedented images of violent events in which gases are accelerated to very high velocities while being rapidly heated to hundreds of thousands of degrees,” posited Bart De Pontieu, the IRIS science lead at Lockheed Martin. “These types of observations present significant challenges to current theoretical models.”
De Pontieu has been examining photos of two kinds of events on the sun that have long been fascinating to astronomers. One is called a prominence, which are cool regions within the interface region that look like giant loops of solar material emerging above the solar surface. When these prominences erupt they result in solar storms that can impact Earth. IRIS reveals highly dynamic and finely structured flows zooming throughout the prominence.
The second type of event is known as a spicule, which are large fountains of gas that zip up from the sun’s surface at 150,000 miles per hour. Spicules may have a role in spreading heat and energy into the sun’s atmosphere. IRIS imaging and spectral data helps astronomers determine at high resolution how the spicules develop.
“We see discrepancies between these observations and the models and that is great news for advancing knowledge,” noted Mats Carlsson, an astrophysicist at the University of Oslo in Norway. “By seeing something we don’t understand we have a chance of learning something new.”
According to Carlsson, who supports the important computer model component of IRIS’ observations, the computer models need a great deal of power function. For example, modeling just an hour of events on the solar furnace can require several months of computer time. For intense computing power, IRIS looks to supercomputers at the space agency’s Ames Research Center, the Norwegian supercomputer collection and the Partnership for Advanced Computing in Europe.
IRIS offers exceptional information about the important layer in between the sun’s surface and its atmosphere to help us figure out how energy travels through the lower levels of the solar atmosphere driving the solar wind and heating the corona.