In addition, it has several rare properties.

Astronomers have just stumbled upon the brightest, most energetic, and heaviest supernova ever. It is a massive star explosion referred to as SN2016aps that occurred about 3.6 billion light-years from Earth. “SN2016aps is spectacular for several reasons,” said researcher Edo Berger. “Not only is it brighter than any other supernova we’ve ever seen, but it also has several features and characteristics that make it very rare compared to other star explosions in the universe.”

Discovery
The particular supernova was first spotted in 2016 using data from the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS). A four-year study followed to study the slow development and significant energy emissions. In addition, old footage was taken from the attic to help the team better understand the nature and explosion of the supernova.

Types of supernovae
A supernova is the phenomenon in which a star explodes spectacularly. The eruption is recognizable by the enormous amount of light that is emitted during this. Supernovae can arise in two ways. For example, a supernova can occur when white dwarfs explode in binary star systems (type Ia). In addition, types II, Ib and Ic occur when massive stars have reached the end of their lives and then form neutron stars or black holes. Types Ib and Ic differ from type II in that their precursors lose material surrounding their central core just before exploding. Type Ib and Ic differ slightly in chemical composition from each other.

In the end, the researchers concluded that SN2016aps may have been caused by the fusion of two massive stars. This created a massive explosion, generating up to ten times the energy of a normal-sized supernova. In the latter supernova, only one percent of the total energy burst can be seen in visible light. But SN2016aps radiated an unprecedented fifty percent of this energy. This is the most light that astronomers have ever seen in a supernova. “The supernova’s intense energy output points to a massive exploded star, which at least had 100 times more mass than our sun at birth,” Berger said.

Artistic impression of supernova SN2016aps. Image: M. Weiss

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Scientists are now trying to understand how this record-breaking explosion happened. Because probably this explosion has not become so big and clear by itself. “Observations during the follow-up study revealed a restless history,” said researcher Matt Nicholl. In the last years before the star exploded, it pulsed violently, throwing some kind of “shell” of gas. “The collision between the explosion debris and this massive shell led to the immense clarity of the supernova,” Nicholl concludes.

Hydrogen gas
The researchers also discovered something surprising about SN2016aps. For example, they found high concentrations of hydrogen gas. Massive stars usually lose most of their hydrogen gas before pulsing. “That SN2016aps retained this hydrogen gas may mean that two less massive stars have fused together,” Berger theorizes. “That’s because lighter stars retain hydrogen longer, while their combined mass is high enough to make the pair unstable.”

Follow-up research is already in the offing. “The discovery of SN2016aps has paved the way for the search for comparable explosions of the first generations of stars,” said Berger. And this may have a follow-up in the short term. “With the upcoming Large Synoptic Survey Telescope (which will be launched in 2022 for the time being, ed.) We can detect such explosions in the first billion years of the universe, ”says Berger. “And there will probably be plenty of similar explosions to be found.”