NASA IRIS Investigates the Sun's Atmosphere: The Heat Bombs that Power a Star

NASA has learned a little bit more about our sun's atmosphere with the help of the Interface Region Imaging Spectrograph (IRIS). They've found five new findings that show how the corona is heated far hotter than its surface, what causes the sun's constant outflow of particles called the solar wind, and what mechanisms accelerate particles that power solar flares.

"These findings reveal a region of the sun more complicated than previously thought," said Jeff Newmark, director for the Heliophysics Division at NASA, in a news release. "Combining IRIS data with observations from other Heliophysics mission is enabling breakthroughs in our understanding of the sun and its interactions with the solar system."

In this case, the researchers found heat pockets of 200,000 degrees Fahrenheit lower in the solar atmosphere ever recorded by previous spacecraft. These heat bombs, which release energy in a short amount of time, may help explain the heating mechanisms throughout the solar atmosphere.

That's not all the researchers found, though. IRIS spotted several small, low lying loops of solar material in the interface region. These loops may give scientists clues as to how the atmosphere is energized. In addition, the researchers found high speed jets at the root of the solar wind. These fountains of plasma shoot out of coronal holes, which are areas of less dense material in the solar atmosphere.

The fifth and final finding that IRIS made highlights the effects of nanoflares throughout the corona. Large solar flares are initiated by something called magnetic reconnection. This occurs when magnetic field lines cross and then realign, with explosive results. This can send particles out into space at nearly the speed of light.

"This 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 De Pontieu, IRIS science lead. "The results focus on a lot of things that have been puzzling for a long time and they also offer some complete surprises."

To learn more about IRIS, visit NASA's website.