Now we know what will happen when the Sun dies

New study suggests that our star will become "one of the most beautiful objects in the night sky."

No one is writing his obituary yet, but scientists have known for a long time that the sun will die-and now we know what will happen next.
A new survey by an international team of astronomers shows that, once it depletes its hydrogen in 5 billion years, our host star is transformed into a huge ring of dust and gas–what astronomers call the planetary nebula.

A photo taken by satellite solar observation Solar Dynamics Observatory SDO shows an exceptionally heavy plasma eruption on the surface of the sun on September 8, 2010. NASA via EPA

"Planetary nebulae are among the most beautiful objects in the night sky," said Albert Zijlstra, professor of astrophysics at the University of Manchester, England, and a member of the team, in email to NBC News MACH. "It's good to know that the sun will one day also make one, even if we're not around to enjoy it!" Zijlstra said the nebula will form from an "envelope" of dust and gas ejected by the setting sun, which will already have swollen to turn into a red giant that extends to the orbit of Venus and perhaps beyond. After ejection, what's left of the sun will heat up as it shrinks into a white dwarf the size of the Earth, but much denser.

of Stock: Ring Nebula
NASA's Hubble space Telescope captured this view of the most famous of all planetary nebulae: the Ring Nebula (M57). In this October 1998 image, the telescope looked down a gas barrel launched by a dying star thousands of years ago. JPL-Caltech/NASA

The nebula will be visible for 10,000 to 20,000 years-a blink of an eye on the cosmic time scale. Its gas and dust disperse slowly, eventually providing the raw material for a new generation of stars and planets. The new discovery, published on May 7 in the journal Nature Astronomy, seems to solve a long debate about the distant future of the sun.

It has long been known that most stars end up producing a planetary nebula, but astronomers thought that the sun-a ball of overheated gas with a diameter 109 times higher than that of the Earth-was too small to form a visible nebula. "The data says you can get bright nebulae from low-mass stars like the sun," Zijlstra said in a statement. "The models said that this was not possible, no less than twice the mass of the sun would give a very weak planetary nebula to see."


For their new research, astronomers have created a series of computer models that show how quickly the dying stars heat up after ejecting their envelopes. The models indicate that the stars heat up three times faster than the previous models indicated, showing that there is still enough heat from the stars the size of our sun to illuminate a nebula. "Our understanding of the fate of the sun has made ping-pong back and forth," said Karen Kwitter, professor of astronomy at Williams College in Williamstown, Massachusetts, in an email, adding that "now, these new models say yes, the Sun will produce a planetary nebula. "

She called the new discovery a "victory" for the little boy. The nebula that our Sun produces will not be as bright as those produced by larger stars. But as Zijlstra told the Guardian, "If you lived in the Andromeda Galaxy at 2 million light-years away, you would still be able to see it."

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