Observational evidence from a neutron star merger has revealed the production of rare heavy elements, including tellurium, advancing our understanding of the universe’s elemental origins. Credit: SciTechDaily.com
Breakthrough discovery puts astronomers one step closer to solving the mystery of the origin of elements that are heavier than iron.
An international team of astronomers — including Clemson University astrophysicist Dieter Hartmann — obtained observational evidence for the creation of rare heavy elements in the aftermath of a cataclysmic explosion triggered by the merger of two neutron stars.
The massive explosion unleashed a gamma-ray burst, GRB230307A, the second brightest in 50 years of observations and about 1,000 times brighter than a typical gamma-ray burst. GRB230307A was first detected by
The breakthrough discovery puts astronomers one step closer to solving the mystery of the origin of elements that are heavier than iron.
“I’m a high energy astrophysicist. I like explosions. I like the gamma rays that come from them. But I’m also an astronomer who really cares about fundamental questions like how did heavy elements form,” Hartmann said.
![Dieter Hartmann](https://scitechdaily.com/images/Dieter-Hartmann-777x517.jpg)
Dieter Hartmann, professor in the Clemson University Department of Physics and Astronomy. Credit: Clemson University
Gamma-Ray Bursts: Windows Into Stellar Processes
Gamma-ray bursts (GRBs) are bursts of gamma-ray light — the most energetic form of light — that last anywhere from seconds to minutes. The first GRBs were detected in the 1960s by satellites built to monitor nuclear testing.
GRBs have different causes.
Long duration GRBs are caused by supernovas, the point when a massive star reaches the end of its life and explodes into a burst of light. Short duration GRBs are caused by the merger of two neutron stars, known as a kilonova, or the merger of a
“The burst itself actually indicated a long duration event, and it should have been a normal supernova-type situation. But it had unusual features. It didn’t quite fit the patterns of long bursts,” Hartmann said. “It turns out that this radioactive cloud, that kilonova afterglow, which had all these nuclear synthetic fingerprints in it, is the signature of a binary merger. The excitement comes from using the Webb to identify a chemical fingerprint that we had expected for short bursts and seeing it inside a long burst.”
The Role of Neutron Star Mergers in Element Formation
Hartmann said the Big Bang produced hydrogen and helium. All other elements were made by stars and processes in the interstellar medium.
“Some of them are massive enough to explode and they return that material to their gaseous environments which later make new stars. So, there’s a cycle in the universe that makes us more enriched in carbon, nitrogen, oxygen, all the things we need,” he said. “We call stars the cauldrons of the universe.”
Thermonuclear reactions, or fusion, make stars shine. That leads successively to the production of more heavy elements, Hartmann said. But when it gets to iron, there isn’t much energy left to squeeze out, he said.
So, where do all the heavy elements such as gold and uranium come from?
“The heavy elements have special origins. There are two processes that dominate. One is called rapid; the other is called slow. We believe the r-process happens in those neutron star mergers,” Hartmann said.
Confirming Theories With Observational Evidence
Theoretical modeling suggested kilonovas should produce tellurium, but the detection of a spectral line by the