Caltech-Led, JPL-Managed NuSTAR Telescope Reveals Hidden Light Shows on the Sun

NuSTAR’s view could help scientists solve one of the biggest mysteries about our nearest star: why the Sun’s outer atmosphere, called the corona, reaches more than a million degrees – at least 100 times hotter than its surface. This has puzzled scientists because the Sun’s heat originates in its core and travels outward. It’s as if the air around a fire were 100 times hotter than the flames.

The source of the corona’s heat could be small eruptions in the Sun’s atmosphere called nanoflares. Flares are large outbursts of heat, light, and particles visible to a wide range of solar observatories. Nanoflares are much smaller events, but both types produce material even hotter than the average temperature of the corona. Regular flares don’t happen often enough to keep the corona at the high temperatures scientists observe, but nanoflares may occur much more frequently – perhaps often enough that they collectively heat the corona.

Although individual nanoflares are too faint to observe amid the Sun’s blazing light, NuSTAR can detect light from the high-temperature material thought to be produced when a large number of nanoflares occur close to one another. This ability enables physicists to investigate how frequently nanoflares occur and how they release energy.

The observations used in these images coincided with the 12th close approach to the Sun, or perihelion, by NASA’s Parker Solar Probe, which is flying closer to the our star than any other spacecraft in history. Taking observations with NuSTAR during one of Parker’s perihelion passes enables scientists to link activity observed remotely in the Sun’s atmosphere with the direct samples of the solar environment taken by the probe.

More About the Mission

NuSTAR launched on June 13, 2012. A Small Explorer mission led by Caltech in Pasadena and managed by JPL for NASA’s Science Mission Directorate in Washington, it was developed in partnership with the Danish Technical University (DTU) and the Italian Space Agency (ASI). The telescope optics were built by Columbia University, NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and DTU. The spacecraft was built by Orbital Sciences Corp. in Dulles, Virginia. NuSTAR’s mission operations center is at the University of California, Berkeley, and the official data archive is at NASA’s High Energy Astrophysics Science Archive Research Center. ASI provides the mission’s ground station and a mirror data archive. Caltech manages JPL for NASA.

For more information on NuSTAR, visit:

www.nustar.caltech.edu