James Webb records kilonova, extremely rare explosion – 10/26/2023 – Science

Thanks to NASA’s James Webb Space Telescope, researchers were able to observe a kilonova, that is, the explosion caused by the merger of a neutron star with a black hole or another star of this type. By the way, a burst of gamma rays, the product of fusion, is exceptionally bright.

This type of fusion attracts the attention of astrophysics, among other things, due to its potential to be a site for the formation of heavy elements. In addition to the glow itself, scientists were able to detect tellurium.

“Webb provides a phenomenal boost and can find even heavier elements,” Ben Gompertz, co-author of the study at the University of Birmingham, UK, told NASA.

The record, which became a publication in Nature magazine, this Wednesday (25), had the participation of the James Webb and Fermi Gamma-ray space telescopes and the Neil Gehrels Swift Observatory.

The gamma ray burst — named GRB 230307A (GRB stands for gamma-ray burst) — is remarkable, according to the researchers. The explosion, detected in March by the Fermi telescope, is about a thousand times brighter than a typical case usually observed by Fermi and the second brightest in more than 50 years of observation.

The duration of the phenomenon — 200 seconds — also drew attention.

Kilonovas are very rare and, consequently, difficult to observe events. Short bursts of gamma rays generally last less than two seconds. Long explosions are usually associated with the death of a massive star and can last minutes.

Interestingly, the two neutron stars that caused the kilonova have their origins very far from the place where they merged. They were thrown out of their original galaxy, which is about 120,000 light-years away, a value equivalent to the diameter of the Milky Way.

In their home galaxy, they were two massive stars that formed a binary system. The two were gravitationally united and left together. The first launch out of the galaxy was associated with the explosion of one of them in a supernova, followed by its transformation into a neutron star; then the second one did the same.

The merger of the two neutron stars came several hundred million years after their launch out of the original galaxy.

Scientists say they hope to find more kilonovae in the future, thanks to complementary work between space and ground-based telescopes.