A research team led by University of Chicago scientists recently made a discovery that could lead to new understanding about a mysterious kind of outer-space explosion.
The scientists appear to have found the first X-rays coming from a specific type of supernova—the explosion of a star that causes a massive increase in brightness. Studying supernovas, which are the largest explosions that take place in space, has shown scientists that we live in an expanding universe and also led to other key discoveries.
The University of Chicago-led team examined a type Ia (one-a) supernova, which is popular with astronomers because it burns at a specific brightness that allows researchers to calculate how far away it is from Earth.
Using recordings from NASA’s Chandra X-ray Observatory, the scientists made two sets of observations, one about a year and a half after the supernova exploded and another 200 days later. They detected a small number of X-rays indicating a supernova surrounded by an accumulation of matter that measured a million times denser than previously thought.
“Although other type Ias with circumstellar material were thought to have similarly high densities, we have never before detected them with X-rays,” said study co-author Vikram Dwarkadas, research associate professor at University of Chicago’s Department of Astronomy and Astrophysics, in a press release.
Such dense material is normally seen only from a different type of supernova called type II, and is created when massive stars begin to lose mass. The ejected mass collects around the star; then, when the star collapses, the explosion sends a shockwave traveling at supersonic speeds into the dense material, producing a shower of X-rays.
Type Ia supernovas, meanwhile, are created when a white dwarf star explodes. It is thought that white dwarfs do not lose mass before they explode, which has made recent discoveries of surrounding material puzzling to scientists, who have guessed that the material must come from companion stars.
But the amount of mass surrounding the supernova examined by the Chicago-led team is far bigger than one could expect from most companion stars, the researchers said.
“This once again raises the question of how exactly these strange supernovas form,” Dwarkadas said.
Future studies looking for X-rays and even radio waves coming off such supernovas could provide new information about how they form, the scientists said.
Their findings were published online Wednesday in the Monthly Notices of the Royal Astronomical Society.
July 25: A team led by Adler Planetarium astronomer Grace Wolf-Chase used a telescope instrument to discover infrared light undetectable to the human eye, revealing new stars in the Milky Way.
June 9: Citizen scientists can help researchers discover new distant galaxies as part of the Adler-led Zooniverse project.
May 11: Northbrook native Beth Moses, chief astronaut instructor for the world's first commercial spaceline, returns to Chicago to receive Adler Planetarium's Women in Space Science Award.