Shocking discovery explains powerful novae

phys.org | 9/5/2017 | Staff


In a typical year, there are around 50 novae, nuclear explosions on the surface of white dwarf stars, in our galaxy. Some of these explosions are so bright and powerful, they exceed the scale of scientific explanation.

Employing two powerful telescopes, astronomers at Michigan State University have proven a theory that explains these super-luminous novae and other astronomical explosions. The results, published in the current issue of Nature Astronomy, indicate that powerful shockwaves amplify the explosions beyond any traditional scale for nuclear explosions.

Astronomers - Energy - Novae - Dwarf - Light

"Astronomers have long thought the energy from novae was dominated by the white dwarf, controlling how much light and energy are emitted," said Laura Chomiuk, MSU astronomer and study co-author. "What we discovered, however, was a completely different source of energy – shockwaves that can dominate the entire explosion."

As the explosion begins, it ejects a cooler, slower wave of gaseous material, relatively speaking. Behind it, though, is a hot, fast wave speeding right behind it. The collision of the two ejections produces a shockwave, which results in a spectacular explosion of heat and light.

Shock - Brighter - Nova - Chomiuk - Speed

"The bigger the shock, the brighter the nova," Chomiuk said. "We believe it's the speed of the second wave that influences the explosion."

This study explains a theory held by Brian Metzger, Columbia University astronomer, who also is a co-author for this paper.

Theory - Astronomers - Explosions - Death - Stars

Now that the theory has been proven, astronomers use novae to better understand other super-charged explosions, like those that mark the death of massive stars in galaxies far away.

"Novae are little laboratories in our galactic backyard that we can use to study some of the most luminous explosions in the universe," Chomiuk said. "As future novae happen, we'll be able to observe them to better understand...
(Excerpt) Read more at: phys.org
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