Low-cost telescope reveals sun's tumultuous 'braids'

Posted by Kate Taylor

In some dramatic images, astronomers have for the first time observed magnetic braids of super-hot matter on the surface of the sun, the first clear evidence of energy transfer from its magnetic field to the solar atmosphere or corona.

The 'solar braiding' had been theorized by researchers, but has only now been seen, in images from NASA's High Resolution Coronal Imager (Hi-C) telescope, launched last July.

"Scientists have tried for decades to understand how the sun's dynamic atmosphere is heated to millions of degrees," says Hi-C principal investigator Jonathan Cirtain.

"Because of the level of solar activity, we were able to clearly focus on an active sunspot, and obtain some remarkable images. Seeing this for the first time is a major advance in understanding how our sun continuously generates the vast amount of energy needed to heat its atmosphere."

The Hi-C mission cost only about $5 million. Nevertheless, its resolution is about five times higher than the imaging instrument aboard NASA's Solar Dynamics Observatory (SDO) launched in February 2010 to study the sun and its dynamic behavior.

Hi-C flew for only about 10 minutes, but captured 165 images of a large, active region in the sun's corona. These pictures show the evolution of the magnetic field, and the repeated release of energy through activity seen on the sun at tempeatures of two to four million degrees.

The observations should lead to better predictions for space weather, as it's the evolution of the magnetic field in the solar atmosphere that drives all solar eruptions.

"The Hi-C observations are part of a technology demonstration that will enable a future generation of telescopes to solve the fundamental questions concerning the heating of the solar atmosphere and the origins of space weather," says Jeffrey Newmark, sounding rocket program scientist at NASA Headquarters in Washington.