Cosmic dust consisting of iron, carbon, and oxygen are an important part of solar system formation. Early galaxies consisted only of gas, and scientists have been trying to figure out where the dust came from for a long time. Now, astronomers have published a paper in Science, showing that they have identified cosmic dust that appears to have survived the massive explosion of a supernova.
“When a supernova explodes, it forms a bunch of dust” said Ryan Lau, an astronomer at Cornell University and lead author of the new study. “But dust is pretty fragile material. So the question is, who’s to say the dust survives this extremely hot, violent environment? And if it does, how much?”
All the heavier elements are created in stars by the process of fusion. Scientists have been trying to explain how these heavier elements became dispersed across the early universe.
The leading theory has always been supernova explosions, but there was never any proof. Scientists were not sure how much dust could actually escape the massive destructive force of the explosion. Earlier theories suggested that up to 80% of dust would be destroyed by shockwaves bouncing back from off the mater surrounding the supernova. Researchers have posited the dust survived this reverse shock phenomena because the dense gas surrounding the explosion slowed the debris, allowing the dust to cool.
Scientists also had speculated that ancient dust came from less powerful stars that don’t go super nova and have a period where they lose mass more gradually, allowing the dust to escape. Lau said that this particular engine for dust creation would be too slow, as these slower burning stars have a much longer life span.
The discovery was made using the Stratospheric Observatory for Infrared Astronomy, or SOFIA, a flying observatory, featuring a Boeing 747 equipped with a special infrared equipment designed to detect cosmic dust. The special plane is a joint project between NASA and the German Aerospace Center. They found the dust surrounding Sagittarius A East supernova remnant, near the center of the Milky Way. The supernova remnant is about 10,000 years old.
Lau added that the 10,000 year-old supernova is the oldest supernova with dust inside it. Roughly 7 to 20 percent of the initial dust mass survived the explosion. Not only does the evidence suggest that dust in the early universe came from supernova, but that more of the dust survived these explosions than was previously imagined.
