KEY POINTS

  • SN 2006gy is one of the brightest supernovae ever discovered
  • The supernova may have been caused by two massive stars that collided
  • One of the stars involved in the collision was as big as the Solar System

A team of scientists may have uncovered the possible cause behind one of the brightest supernova events ever discovered. According to the scientists, one of the stars that caused the cosmic event could be as big as the entire Solar System.

In a new study published in the journal Science, scientists focused on the supernova known as SN 2006GY, which is about 238 million light-years from Earth. As super-luminous supernovae, SN 2006gy’s brightness can rival that of an entire galaxy.

Through special telescopes, such as NASA’s Chandra X-ray Observatory, the scientists were able to observe SN 2006gy. When it was first discovered, scientists initially thought that it was made by a star that 150 times more massive than the Sun. This was mainly due to the scale of the explosion it displayed.

"This was a truly monstrous explosion, a hundred times more energetic than a typical supernova,” Nathan Smith from UC Berkley, who was not part of the new study, said in a statement. “That means the star that exploded might have been as massive as a star can get, about 150 times that of our Sun. We've never seen that before.”

After closely examining the supernova, a team of scientists from Japan and Sweden discovered emission lines composed of iron within the massive cosmic structure. They learned that in order for these lines to emerge, large amounts of iron about a third of the Sun’s mass was needed. This clue helped the scientists narrow down a possible explanation regarding the supernova’s formation.

According to the scientists, SN 2006gy may have been a double star before it went supernova. One of these stars was a white dwarf that was about as big as Earth. The other one was a hydrogen-rich star that was as large as the Solar System.

The scientists explained that as these two stars orbited one another, the white dwarf spiraled towards the larger star due to its expansion. Eventually, the former reached the center of the latter and exploded. It resulted in an extremely bright explosion and the appearance of iron-rich emission lines.

“That a white dwarf can be in close orbit with a massive hydrogen-rich star, and quickly explode upon falling to the center, gives important new information for the theory of double star evolution and the conditions necessary for a white dwarf to explode,” Anders Jerkstrand, the study’s co-author, explained.

supernova-breakout
The brilliant flash of an exploding star's shockwave — what astronomers call the hock breakout — is illustrated in an artist concept. NASA/JPL