Strange Activity Surrounds Dying Star
New York (United States):
An ancient, near-death star with a disc of metal-rich dust orbiting around it has recently been discovered by astronomers. The dust's origin is a mystery, though, as it should have been sucked into the star within a few hundred years of the star's death.
Even though this anomaly is about 82 light-years away and several billion years old, astronomers think it could provide a preview of our solar system's future when the Sun dies five to six billion years from now.
Between three and five billion years ago, GD 362 was a star much like our Sun, only seven times more massive. It takes a lot of energy to maintain that much mass, and eventually GD 362's nuclear power plant ran out of fuel and the star could no longer produce enough heat energy to keep its outer layers from crashing inward.
Once the fuel ran out, the star lost plenty of mass and heat, and shriveled into a white dwarf – the final stage of star evolution where the star burns out and dies. Enough heat gets released during this process to vaporize any surrounding dust, rocks, and planets, leaving behind a disc of dust.
This dust usually gets sucked into the newly formed white dwarf and incinerated within a few hundred years.
But when GD 362 went through this process five billion years ago, the dust never cleared up. And astronomers don't know how a dead star roughly the size of Earth has been able to sustain a disc the size of Saturn's rings for so long.
"Where the disc comes from is the $64,000 question," Ben Zuckerman of UCLA told SPACE.com. "However, we believe that it's from a planetary system around this star. Something – comets, asteroids, or planets – is getting ground up into dust and being pulled into the star."
Sept 13, 2005
Space.com
New York (United States):An ancient, near-death star with a disc of metal-rich dust orbiting around it has recently been discovered by astronomers. The dust's origin is a mystery, though, as it should have been sucked into the star within a few hundred years of the star's death.
Even though this anomaly is about 82 light-years away and several billion years old, astronomers think it could provide a preview of our solar system's future when the Sun dies five to six billion years from now.
Between three and five billion years ago, GD 362 was a star much like our Sun, only seven times more massive. It takes a lot of energy to maintain that much mass, and eventually GD 362's nuclear power plant ran out of fuel and the star could no longer produce enough heat energy to keep its outer layers from crashing inward.
Once the fuel ran out, the star lost plenty of mass and heat, and shriveled into a white dwarf – the final stage of star evolution where the star burns out and dies. Enough heat gets released during this process to vaporize any surrounding dust, rocks, and planets, leaving behind a disc of dust.
This dust usually gets sucked into the newly formed white dwarf and incinerated within a few hundred years.
But when GD 362 went through this process five billion years ago, the dust never cleared up. And astronomers don't know how a dead star roughly the size of Earth has been able to sustain a disc the size of Saturn's rings for so long.
"Where the disc comes from is the $64,000 question," Ben Zuckerman of UCLA told SPACE.com. "However, we believe that it's from a planetary system around this star. Something – comets, asteroids, or planets – is getting ground up into dust and being pulled into the star."
Sept 13, 2005
Space.com
