STEREO-B image of Sagittarii 2012 (STEREO/SECCHI/NASA/NRL)
While on duty observing the Sun from its position in solar orbit, NASA’s STEREO-B spacecraft captured the sudden appearance of a distant bright object. This flare-up turned out to be a nova — designated Sagittarii 2012 — the violent expulsion of material and radiation from a re-igniting white dwarf star.
Unlike a supernova, which is the cataclysmic collapse and explosion of a massive star whose core has finally fused its last, a nova is the result of material falling onto the surface of a white dwarf that’s part of a binary pair. The material, typically hydrogen and helium gas, is drawn off the white dwarf’s partner which has expanded into a red giant.
Eventually the white dwarf cannot contain all of the material that it has sucked in from its neighbor… material which has been heated to tremendous temperatures on its surface as it got compressed further and further by the white dwarf’s incredibly strong gravity. Fusion occurs on the dwarf’s outermost layers, blasting its surface out into space in an explosion of light and energy.
Read More and watch the video Here:http://phys.org/news/2012-05-nasas-stereo-nova.html