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Detailed images capture mysterious region of the sun

July 25, 2013|By Melissa Pandika

NASA offered a peek of the first batch of images and physical data from its new IRIS solar observatory, the first detailed look at a little-understood layer of the sun sandwiched between the surface and glowing outer corona.

Researchers have just begun to analyze the data from IRIS, which is known officially as the Interface Region Imaging Spectrograph. The ultimate goal of the mission is to shed light on how this mysterious layer – known as the interface region -- powers the sun’s atmosphere and churns the solar winds that flow through the entire solar system. That could help scientists forecast solar flares and other destructive behaviors that can disrupt and disable satellites, power grids and GPS services.

NASA launched the 7-foot long, 440-pound IRIS on June 27, and its telescope cover opened July 17. From its perch above Earth, IRIS will continually deliver solar observations throughout its two-year mission.

On Thursday, scientists unveiled one photo showing activity in a region bearing two sunspots, which appeared as dark patches. IRIS revealed “many, many more” sunspots than the team had anticipated, said Alan Title, IRIS principal investigator and a physicist at the Lockheed Martin ATC Solar and Astrophysics Laboratory in Palo Alto.

The team members want to understand what these roughly 150-mile-wide sunspots are doing, especially their physical processes and their role in heating the sun’s outer atmosphere, Title said.

He and his colleagues have begun running computer simulations of sunspot activity so that they can play it back slower and examine it more carefully. Although the simulations hint at what’s going on, the scientists stopped short of offering any interpretations until they’ve further analyzed the data.

The images also show numerous thin, fibril structures that have never been observed before. These mysterious structures reveal stark contrasts in density and temperature, even between areas a few hundred miles apart.

A looped, slowed-down video (above) showed the sun’s swirling atmosphere in action.

Other images NASA has yet to reveal show a “surprising” abundance of fibril and other structures in remarkable detail, said IRIS science lead and Lockheed Martin astrophysicist Bart DePontieu. “We’re seeing a lot more structures than we had anticipated,”  he said, even in areas once thought be quiet. Some of these structures include filaments and fountains of gas, he added.

IRIS also captured wavelength data indicating the differences in brightness and temperature between the surface and corona at various locations. This information will help scientists understand how the interface region heats plasma from 6,000  to millions of degrees Fahrenheit and propels it into the corona.

“How the atmosphere is heated to millions of degrees is one of the mysteries of solar physics,” DePontieu said.

The high quality of the spectral data revealed a more complex picture of the sun’s physical processes than the research team anticipated. “We’re seeing small events that are dynamic and energetic and need more analysis to understand,” DePontieu said.

A computer simulation modeling the sun’s physical conditions yielded similar wavelength data.  But the team is most excited  about the discrepancies between the model and their observations, DePontieu said. “They tell us we’re missing something in our understanding,” he said.

IRIS will deliver near-continuous solar observations throughout its two-year mission, pointing its telescope toward a different target each day. It will capture a new image every five to 10  seconds and new wavelength data about every one to two seconds.

Return to Science Now.

melissa.pandika@latimes.com

Twitter: @mmpandika

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