io9 reported Astronomers Observe An Expanding Nova Fireball For The First Time "An international team of astronomers have finally caught a glimpse of an expanding thermonuclear fireball from an exploding white dwarf. It's the first time this kind of data has ever been captured, allowing the researchers to study how the fireball evolves and rapidly expands into space."
"This particular nova is located about 14,800 light-years from here in the constellation of Delphinus (the Dolphin), so technically speaking it exploded some 15,000 years ago. The astronomers observed the event on August 14th, 2013."
"The data showed that the ferocity of the initial expansion was intense, engulfing a region the size of the Earth's orbit within a day, and passing Jupiter's orbit in less than two weeks. At the 43-day mark, the fireball had expanded to the size of Neptune's orbit."
"We found the initial nova explosion wasn't spherical, giving the fireball a slightly elliptical shape," noted Australian National University's Michael Ireland in an ABC News article. "This happens because the white dwarf's atmosphere is spinning, and there's a disk of accreted material falling onto it from the companion star, so there's a lot happening to prevent the system from being spherical when it goes bang."
"What's more, mysterious multiple shells were seen as the nova exploded. A main shell expanded at about 600 kilometers per second, but there were also semi-transparent shells further out going even faster. The astronomers observed the optically thick inner shell and the transparent outer shells expanding at the same time — and they're not entirely sure what they are."
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