NASA Chandra Observatory Sheds Light on What Triggered a Star Explosion

NASA's Chandra X-ray observatory is combing the universe to shed some light on stars and other cosmic bodies. Now, it's offered a glimpse into the environment of a star before it exploded and caused one of the closest supernovas seen in decades.

"While it may seem a bit odd, we actually learned a great deal about this supernova by detecting absolutely nothing," said Raffaella Margutta of the Harvard-Smithsonian Center for Astrophysics (CfA), who led the study, in a news release. "Now we can essentially rule out the explosion was caused by a white dwarf continuously pulling material from a companion star."

The supernova in question is a Type Ia supernova. Usually, these supernovas can be triggered when a white dwarf takes on too much mass from its companion star, immersing it in a cloud of gas that produces a significant source of X-rays after the explosion. The researchers used telescopes to search the nearby Messier 82 galaxy for this sort of X-ray source. Yet no such source was found and, in fact, the astronomers found a region around the supernova devoid of materials.

This told the astronomers that the supernova, called SN 2014J, could have been caused by the merger of two white dwarf stars. This would have resulted in little or no X-rays after the explosion.

"Being able to eliminate one of the main possible explanations for what caused SN 2014J to explode is a big step," said Atish Kamble, co-author of the new study, in a news release. "The next step is to narrow things down even further."

Understanding how Type Ia supernovas explode is a huge step when it comes to using them for cosmology. These supernovas are used as cosmic distance markers and allow scientists to learn a bit more about the universe's expansion.

The findings are published in The Astrophysical Journal.