An artist’s impression of two neutron stars merging in a cataclysmic blast, producing strontium and confirming heavy element creation in such extreme-energy events. Image: ESO/L. Calçada/M. Kornmesser
Probing light from a kilonova blast in the wake of a cataclysmic neutron star merger, astronomers have identified strontium in spectra captured by the X-shooter instrument on the European Southern Observatory’s Very Large Telescope, confirming heavy elements are indeed formed in such extreme events.
The source, known as GW170817, was detected by gravitational waves in 2017, triggered by the merger of two neutron stars. The X-shooter instrument and others monitored the emerging kilonova blast, on the lookout for heavy elements. While there were indications of such elements, researchers were unable to isolate individual signatures until now.
“By reanalysing the 2017 data from the merger, we have now identified the signature of one heavy element in this fireball, strontium, proving that the collision of neutron stars creates this element in the universe,” said Darach Watson of the University of Copenhagen, lead author of a paper in the journal Nature.
“This is the final stage of a decades-long chase to pin down the origin of the elements,” he said. “We know now that the processes ...