If there’s one thing massive stars love doing toward the ends (and climaxes) of their lives, it’s exploding outward against the force of gravity in a KABLAM! so huge it outshines its host galaxy. But while we’re used to hearing about gargantuan supernovae, scientists have theorized a type of stellar explosion that’s even bigger: a hypernova. And a team of astronomers says it now has direct evidence the cosmic phenomenon really does occur.
New Atlas picked up on the astronomers’ claim, which they’ve outlined in a study published in the journal Nature. David Yong, Gary Da Costa, and Chiaki Kobayashi from Australia’s ARC Centre of Excellence in All Sky Astrophysics in 3 Dimensions (or ASTRO 3D) led the study. And they say this hypernova— or “collapsar”—is unique from any other supernova astronomers have detected.
Yong et al. looked at one particular star in the Milky Way, SMSS J200322.54-114203.3, for evidence of the hypernova. (The star is in the crosshairs in the image above.) The astronomers pinpointed the star because it is extremely metal-poor; meaning that the star has a relatively low abundance of certain metal elements, like zinc and uranium. It also, however, has a relatively rich abundance of elements heavier than iron; a mix that doesn’t add up because those elements in those proportions can’t be generated by any known supernova type.
The astronomers believe only a hypernova could’ve generated that kind of elemental makeup. (After stars explode, their constituent matter coalesces again thanks to gravity. In the process, the matter becomes new stars, as well as planets and other celestial bodies.) “This is the first time we have seen the chemical fingerprint of such a hypernova explosion,” study author, Dr. Simon Murphy, said in a press release.
A new type of massive explosion explains mystery star, @ARC_ASTRO3D scientists David Yong, Chiaki Kobayashi & Gary da Costa reveal in @Nature. A magneto-rotational hypernova erupted soon after Big Bang. https://t.co/llPJSUCguu @StromloANU @ourANU @UniofHerts pic.twitter.com/MsuKnXzhOq
— ASTRO 3D (@ARC_ASTRO3D) July 8, 2021
As for what caused the hypernova, the astronomers say it must have been the explosion of a highly magnetized and fast-rotating star. One that was 25 times the mass of the Sun. Unlike other stars similar to SMSS J200322.54-114203.3, the astronomers say a neutron-star merger, while often an explanation for this kind of stellar makeup, doesn’t work in this situation.
“We now find the observational evidence for the first time directly indicating that there was a different kind of hypernova producing all stable elements in the periodic table at once,” Kobayashi added in the press release. “It is the only thing that explains the results.”