for National Geographic News
In an example of galactic foreshadowing, scientists have gazed out at the stars and glimpsed how our solar system might look in several billion years.
An unusual ring of metal-rich gas orbiting a white dwarf—the remains of a burned-out star of modest mass—has been spied within the constellation Virgo.
The white dwarf, called SDSS 1228+1040, sits about 463 light-years from our solar system (explore an online star chart).
Scientists believe the solar remnant formed from a star that was about four to five times as massive as the sun.
Interactions between at least one planetlike object and an asteroid that once orbited the white dwarf at a great distance are responsible for the ring of metal-rich gas.
In a paper appearing in tomorrow's issue of the journal Science, astronomers describe how the process that likely formed this unusual system could provide insight into how our solar system will eventually meet its end.
When small to medium-size stars burn up all their hydrogen, they expand like balloons into so-called red giants, destroying everything in their path.
These dying stars can become hundreds to thousands of times the size of our sun.
Eventually the outer layers of a red giant disperse and leave behind a dense core—a white dwarf—that usually contains roughly the same mass of our sun in a body the size of Earth.
As it expanded, the red giant version of SDSS 1228+1040 probably destroyed everything in its orbit out to about 500 million miles (800 million kilometers), according to the scientists.
What's so unusual about SDSS 1228+1040 is the metal-rich disk of gas that orbits close to the white dwarf, roughly 500,000 miles (800,000 kilometers).
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