Researchers have examined the creation of rare chemical elements in the second-brightest gamma-ray burst ever seen.
The second-brightest gamma-ray burst (GRB 230307A), caused by a neutron star merger, has shed light on how chemical elements are made.
The researchers observed the burst using an array of ground and space-based telescopes. These include NASA’s James Webb Space Telescope, Neil Gehrels Swift Observatory, and the Fermi Gamma-ray Space Telescope.
In the paper, ‘Heavy element production in a compact object merger observed by JWST,’ the team revealed that they found the heavy chemical element tellurium in the aftermath of the gamma-ray burst.
It is likely that other elements, such as iodine and thorium, which are needed to sustain life on Earth, are amongst the material ejected by the explosion.
The second time individual heavy elements have been detected after a neutron star merger
GRB 230307A was the second-brightest gamma-ray burst ever observed. It was recorded to be over a million times brighter than the entire Milky Way Galaxy combined.
This is the second time individual heavy elements have been detected using spectroscopic observations after a neutron star merger. The observations will help researchers learn how these chemical elements needed for life are formed.
Dr Ben Gompertz, Assistant Professor of Astronomy at the University of Birmingham, and co-author of the study, explained: “Gamma-ray bursts come from powerful jets travelling at almost the speed of light – in this case driven by a collision between two neutron stars.
“These stars spent several billion years spiralling towards one another before colliding to produce the gamma-ray burst we observed in March this year.
“The merger site is the approximate length of the Milky Way (about 120,000 light-years) outside of their home galaxy, meaning they must have been launched out together.
“Colliding neutron stars provide the conditions needed to synthesise very heavy elements, and the radioactive glow of these new elements powered the kilonova we detected as the blast faded. Kilonovae are extremely rare and very difficult to observe and study, which is why this discovery is so exciting.”
GRB 230307A: An unusual observation
Lasting 200 seconds, the gamma-ray burst is categorised as long-duration. This is unusual because short gamma-ray bursts, which last less than two seconds, are usually caused by neutron star mergers.
The explosive death of a massive star usually causes long gamma-ray bursts like GRB 230307A.
The team’s future plans
Now, the team is looking to learn more about how neutron star mergers work and how they power these huge gamma-ray bursts.
Dr Samantha Oates, a co-author of the study while a postdoctoral research fellow at the University of Birmingham (now a lecturer at Lancaster University) said: “Just a few short years ago, discoveries like this one would not have been possible, but thanks to the James Webb Space Telescope we can observe these mergers in exquisite detail.”
Dr Gompertz concluded: “Until recently, we didn’t think mergers could power gamma-ray bursts for more than two seconds.
“Our next job is to find more of these long-lived mergers and develop a better understanding of what drives them – and whether even heavier elements are being created. This discovery has opened the door to a transformative understanding of our Universe and how it works.”
