The Solar Corona In Hi-Defintion.
These photos of the solar corona, or million-degree outer atmosphere, show the improvement in resolution offered by NASA's High Resolution Coronal Imager, or Hi-C (bottom), versus the Atmospheric Imaging Assembly on NASA's Solar Dynamics Observatory (top). Credit: NASA
Earlier this month a sounding rocket lifted off from White Sands Missile Range in New Mexico. Onboard was NASA’s High Resolution Coronal Imager (Hi-C) telescope loaded with sophisticated imaging gear. Weighing in at a little more than 210 kg and measuring out at about 10 meters long, the new telescope imaging system took 165 pictures of the Sun during its brief 620-second flight… and made history. “Even though this mission was only a few minutes long, it marks a big breakthrough in coronal studies,” said Smithsonian astronomer Leon Golub (Harvard-Smithsonian Center for Astrophysics), one of the lead investigators on the mission.
“These revolutionary images of the Sun demonstrate the key aspects of NASA’s sounding rocket program, namely the training of the next generation of principal investigators, the development of new space technologies, and scientific advancements,” said Barbara Giles, director for NASA’s Heliophysics Division at NASA Headquarters in Washington.
Understanding the Sun and how it impacts Earth’s environment is tantamount to the new study. The solar corona consists of an envelope of million-degree ionized gases called plasma. This region is so hot that the light it produces is more focused at extreme ultra-violet and x-ray wavelengths. For many years researchers have been endeavoring to understand why the corona produces such copious heat and why it has such unpredictable storms. Huge active regions, such as solar flares and coronal mass ejections are capable of disrupting Earth… and the Hi-C telescope was designed to investigate fine structures thought to be responsible for these violent events.
“The phrase ‘think globally, act locally’ applies to the Sun too. Things happening at a small, local scale can impact the entire Sun and result in an eruption,” explained Golub.
According to the NASA news release, the telescope acquired data at a rate of roughly one image every 5 seconds. Its resolution is approximately five times more detailed than the Atmospheric Imaging Assembly (AIA) instrument flying aboard NASA’s Solar Dynamics Observatory (SDO). For comparison, AIA can see structures on the Sun’s surface with the clarity of approximately 1100 kilometers and observes the Sun in 10 wavelengths of light. Hi-C can resolve features down to roughly 217 kilometers, but observed the Sun in just one wavelength of light.
The target for the mission was chosen on launch day – an active region on the Sun near sunspot NOAA 1520 – picked because of its large size and violent nature. The Hi-C telescope then began its series of high-resolution images at a wavelength of 19.3 nanometers (25 times shorter than the wavelength of visible light). What they revealed was next to incredible… twisting magnetic fields ushering the solar plasma into series after series of complex structures.
“We have an exceptional instrument and launched at the right time,” said Jonathan Cirtain, senior heliophysicist at NASA’s Marshall Space Flight Center in Huntsville, Ala. “Because of the intense solar activity we’re seeing right now, we were able to clearly focus on a sizeable, active sunspot and achieve our imaging goals.”
Although the flight only lasted 330 seconds, the images taken through the Hi-C telescope will provide the solar scientific community information that will take months to sift through.
“The Hi-C flight might be the most productive five minutes I’ve ever spent,” Golub smiled.
Original Story Source: NASA News Release.
