Sounding Rocket Flight Provides Important Clues To Coronal Heating, And Points The Way To Future Solar Missions

PALO ALTO, Calif., Jan. 23, 2013 /PRNewswire/ -- A NASA sounding rocket flight in 2012 captured five minutes of the highest-resolution images ever taken of the Sun's million-degree outer atmosphere, the corona. The new images have provided tantalizing hints of another mechanism that likely contributes to the heating of the solar corona. In a paper published today in the journal Nature, researchers from multiple government and private institutions – including the Solar & Astrophysics Lab at the Lockheed Martin Advanced Technology Center (ATC) in Palo Alto – have analyzed the data and identified a likely source of heat that replenishes the corona. The clarity of the new images will also help scientists better predict when violent solar eruptions threaten Earth's space environment.

On July 12, 2012, NASA scientists launched a solar telescope called Hi-C, for High Resolution Coronal Imager, into space, aboard a Black Brant sounding rocket from the White Sands Missile Range in New Mexico. The mission took just 620 seconds for its flight, spending about half of that time high enough that Earth's atmosphere would not block ultraviolet rays from the Sun. By looking at a specific range of UV light, HI-C scientists were able to observe fundamental structures on the Sun, as narrow as 150 miles across.

The visible surface of the Sun, called the photosphere, is relatively cool, at 6,000 degrees C, but is enveloped by the much hotter gas of the corona. One of the most enduring mysteries in solar physics is why the Sun's corona is millions of degrees hotter than its surface. During the past few decades, a wide variety of theoretical models to explain this enigma have been proposed, but the lack of detailed observations of the fundamental heating process has left the question still open.

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