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Astronomers have  discovered pulsations from the crystalized remnant of a burnt-out star, GD 518,  roughly 170 light years from Earth in the constellation Draco, but far too faint to be seen without a telescope. It is a white dwarf, a star at the end of its life cycle that is essentially just a burnt-out core, the ashy byproduct of previous epochs of nuclear fusion. The star is unique in that much of it is likely suspended in a state more akin to a solid than a liquid or gas. The interiors of dying stars can become crystalized similar to the way in which frigid water freezes into ice, like the slow formation of glaciers in cooling ocean water.

 The astronomers at University of Texas at Austin and colleagues have used the 2.1-meter Otto Struve Telescope at the university’s McDonald Observatory Texas made their discovery in collaboration with astronomers from Brazil’s Universidade Federal do Rio Grande do Sul, the University of Oklahoma, and the Smithsonian Astrophysical Observatory. The findings appear in the current issue of The Astrophysical Journal Letters.

"GD 518 is special because it is a very massive white dwarf: It has about 1.2 times the mass of the Sun, packed into a volume smaller than Earth," said lead author J.J. Hermes, a graduate student at The University of Texas at Austin. "Few white dwarfs are endowed with so much mass, and this is by far the most massive white dwarf discovered to pulsate."

Our Sun will only get hot enough in its center for nuclear fusion to burn hydrogen into helium, and in turn the helium to carbon and oxygen. The Sun will end its life in more than five billion years as a white dwarf with its central regions composed mostly of the nuclei of carbon and oxygen atoms.

But unlike the Sun, the star that died to become the white dwarf GD 518 was so massive —probably more than seven times the Sun’s mass — that it burned elements heavier than carbon and oxygen, and is now likely a white dwarf composed of oxygen and neon nuclei.

The discovery of pulsations —periodic brightness changes on the surface of a star that, in this case, keep a regular tune every 400-600 seconds — will allow astronomers an unprecedented opportunity to understand what makes up this highly evolved star’s interior.

Team member Barbara Castanheira is a postdoctoral researcher with McDonald Observatory. "Like a child at a museum, astronomers are only allowed to look, not touch, when they perform experiments," Castanheira said. "This means we usually can only understand the surface of a star. Pulsations, like the sound of a bell, tell us more of the story, since they can unravel secrets about the much deeper interior of a star."

White dwarf stars no longer fuse elements in their interior to generate energy; they simply cool, like coal embers removed from a fire. But at a certain point the atomic nuclei in the star's interior get cool enough to begin to settle into a lattice structure and crystalize, just like water freezing into ice. This happens sooner in the interiors of more massive white dwarfs, and in the case of GD 518, it has likely started before the star had the right conditions to excite pulsations. The transition to a solid-like star should also affect the way the white dwarf vibrates from these pulsations.

Astronomers now face the difficult task of matching the pulsation periods observed in the star with those predicted by different models of the structure of its interior. The discovery observations show promise in this direction, Hermes said.

"We see evidence that the strength of pulsations in this star are very inconsistent; some nights the star is as still as a whisper," he said. "This could be because the white dwarf is highly crystalized, and the pulsations are only allowed to propagate in a tiny bit of the outermost parts of the star. They thus have little inertia, and are more susceptible to changes than the pulsations in a typical pulsating white dwarf."

University of Texas astronomers will continue watching GD 518 from McDonald Observatory, listening closely for any new notes that can unravel the song being sung by light from this ultramassive dying star.

The image from NASA's Chandra (blue) and Spitzer (green and red-yellow) space telescopes at the top of the page shows the dusty remains of a collapsed star, a supernova remnant called G54.1+0.3. The white source at the center is a dead star called a pulsar, generating a wind of high-energy particles seen by Chandra in blue. The wind expands into the surrounding environment. The infrared shell that surrounds the pulsar wind, seen in red, is made up of gas and dust that condensed out of debris from the supernova explosion. A nearby cluster of stars is being engulfed by the dust.

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Like puppies, kids are wildly energetic and easy to fool. My siblings once recited a "hilarious joke" to my toddler cousin: an arduous, incomprehensible story, ending with the punchline: "Soap! It was the soap!" They then burst into laughter, on cue, and my amusingly gullible cousin followed suit, laughing uproariously.

Such is the idea with the new app, Magic Story Maker. The app comes equipped with three storybook themes, and all you have to do is choose your favorite news stories to plug in. Sure, parents can tolerate reading Sylvester and the Magic Pebble to their kids once or twice, but wouldn't pretty pictures suffice? All the while you can be keeping yourself up-to-date on your daily news, child none the wiser--heck, hearing about four-quark particles might even fool me if accompanied by pretty, fantastical illustrations.

"Plus you'll be doing your child a favor. Research indicates that reading articles such as these helps build vocabulary, which leads to higher IQs later in life," claims the app's description. "It makes sense-the child who is read science news every day is going to be much smarter than the one who learns that a cow goes moo 8,000 times in a year."

The app is available for just $1.99 here-just imagine how much more you'll know about current events! And plus, this feels way less unethical than that other tongue-in-cheek bedtime book....

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