An article published in the journal “Nature” reports the detection of heavy elements including tellurium ejected from a kilonova, the merger between two neutron stars. A team of researchers started from the gamma-ray burst cataloged as GRB 230307A to examine data collected by ground-based and space telescopes which made it possible to identify the characteristics of a kilonova at the origin of that very powerful explosion, which lasted about 200 seconds in the second brightest gamma-ray burst detected so far.

The James Webb Space Telescope made it possible to examine the environment around the kilonova with its NIRCam and NIRSpec instruments, detecting the spectroscopic traces left in the emissions from materials ejected at high speed. For the first time, tellurium, a very rare element on Earth, was detected. Webb also made it possible to ascertain that the pair of neutron stars that merged was ejected from its home galaxy hundreds of millions of years ago.