Scientists have made a significant observation of the creation of rare chemical elements in a gamma-ray burst, shedding new light on the process of heavy element formation. The study focused on the gamma-ray burst GRB 230307A, which was caused by the merger of two neutron stars. The explosion was observed using a combination of ground and space-based telescopes, including NASA’s James Webb Space Telescope, Fermi Gamma-ray Space Telescope, and Neil Gehrels Swift Observatory.
In their findings published in Nature, the international research team, which included experts from the University of Birmingham, reported the detection of the heavy chemical element tellurium in the aftermath of the explosion. The researchers also believe that other elements essential for sustaining life on Earth, such as iodine and thorium, were likely ejected during the explosion, which is also known as a kilonova.
Dr. Ben Gompertz, Assistant Professor of Astronomy at the University of Birmingham and co-author of the study, explained that gamma-ray bursts are produced by powerful jets traveling at nearly the speed of light, in this case resulting from the collision between two neutron stars. These stars spent billions of years spiraling towards each other before colliding and producing the observed gamma-ray burst. The merger site is located outside their home galaxy at a distance roughly equivalent to the length of the Milky Way.
The collision of neutron stars provides the necessary conditions for synthesizing very heavy elements, and the radioactive glow emitted by these new elements powered the kilonova observed after the blast faded. Kilonovae are extremely rare and challenging to observe and study, making this discovery particularly exciting.
GRB 230307A was one of the brightest gamma-ray bursts ever observed, being over a million times brighter than the entire Milky Way Galaxy combined. This is only the second time that individual heavy elements have been detected through spectroscopic observations after a neutron star merger, providing valuable insights into the formation of these essential building blocks for life.
Lead author of the study, Professor Andrew Levan from Radboud University in the Netherlands, highlighted the significance of this discovery in filling in the gaps of our understanding of element formation, stating that it is now possible to start unraveling where everything was made thanks to the James Webb Telescope.
The duration of GRB 230307A, which lasted for 200 seconds, categorizes it as a long-duration gamma-ray burst. This is unusual, as short gamma-ray bursts, lasting less than two seconds, are more commonly caused by neutron star mergers. Long gamma-ray bursts like this one are typically associated with the explosive death of a massive star.
The researchers are now focused on further studying the mechanisms and power sources behind these neutron star mergers and the resulting element-generating explosions. Dr. Samantha Oates, a co-author of the study, emphasized the importance of the James Webb Space Telescope in enabling detailed observations of these mergers.
Dr. Gompertz concluded by stating that until recently, it was believed that mergers could not power gamma-ray bursts for more than two seconds. The next step is to identify more long-lived mergers and gain a better understanding of their driving forces, as well as investigating the possibility of even heavier elements being created. This discovery marks a significant milestone in advancing our understanding of the universe and its workings.