New composite X-ray image reveals active regions of Sun

LLANDUDNO, Wales, July 9 (UPI) -- A new image of the sun combines X-ray observations made by a number of instruments. The composite image shows the sun's flaring, active regions.

"We can see a few active regions on the Sun in this view," Ianin Hannah, an astronomer at the University of Glasgow, said of the image in a press release. "Our Sun is quietening down in its activity cycle, but still has a couple of years before it reaches a minimum."

On Wednesday, July 8, Hannah presented the image to attendees of the National Astronomy Meeting in Llandudno, Wales.

The composite rendering combines imaging results from NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) and the X-ray instrument on Japan's Hinode spacecraft. NuSTAR reveals the sun's high-energy X-rays (imaged in blue), while Hinode shows the sun's low-energy X-rays in green. Yellow and orange colors represent ultraviolet rays observed by NASA's Solar Dynamics Observatory.

NuSTAR -- which spends most of its time observing black holes -- is so sensitive that it has difficulty detailing the massive flares that send solar storms towards Earth. But researchers have been trying to use the telescope to detect hypothesized nanoflares, tiny flares that scientists believe explain why the sun's corona is so hot.

"What's great about NuSTAR is that the telescope is so versatile that we can hunt black holes millions of light-years away and we can also learn something fundamental about the star in our own backyard," said Brian Grefenstette, a NuSTAR scientist and astronomer at the California Institute of Technology.

Currently, the sun's still-significant electromagnetic activity -- as evidenced by the recent arrival of sizable storms -- is making it difficult to study the sun's more subtle flares.

"We still need the Sun to quieten down more over the next few years to have the ability to detect these events," said Hannah.