Using multiple observatories, astronomers directly detect tellurium in two merging neutron stars.
An extraordinary burst of high-energy light in the sky pointed astronomers to a pair of metal-forged neutron stars 900 million light-years from Earth.
In a study recently published in Naturean international team of astronomers, including scientists from The team found that as the stars circled each other and eventually merged, they emitted a huge amount of energy in the form of GRB. And for the first time, astronomers have directly detected signs of heavy metals in the stellar aftermath. Specifically, they picked up a clear signal of tellurium, a heavy, slightly toxic element that is rarer than platinum on Earth but thought to be abundant throughout the universe.
Astronomers estimate that the merger released enough tellurium to equal the mass of 300 Earths. And if tellurium is present, the fusion must have produced other closely related elements, such as iodine, which is an essential mineral nutrient for much life on Earth.
Global Astronomical Efforts
The discovery was made through the collective effort of astronomers around the world, using NASA’s James Webb Space Telescope (JWST), as well as other ground- and space-based telescopes, including NASA’s TESS satellite (an MIT-led mission) and the Very Large Telescope (VLT) in Chile, which MIT scientists used to contribute to the discovery.
“This discovery is a major step forward in our understanding of where heavy elements form in the Universe and demonstrates the power of combining observations at different wavelengths to reveal new insights into these extremely energetic explosions.” from the Benjamin Schneider study. a postdoctoral fellow at MIT’s Kavli Institute for Astrophysics and Space Research.
Schneider is one of many researchers from various institutions around the world who contributed to the study, which was led by Andrew Levan of Radboud University in the Netherlands and the
“All at once”
The initial explosion was detected on March 7, 2023, by
The ultra-bright explosion was also exceptionally long, lasting 200 seconds, while
At MIT, Schneider and Fausnaugh joined the multifaceted search. Shortly after Fermi’s initial detection, Fausnaugh checked whether the explosion appeared in data obtained by Fermi.
Tracking the neutron star merger
Where did the merger itself originate? To do this, astronomers turned to JWST’s deep-field vision, which can see farther into space than any other telescope. Astronomers used JWST to observe GRB 230307A, hoping to identify the host galaxy where the neutron stars originated. The telescope’s images revealed that, strangely, the GRB appeared to be unattached to any host galaxy. But there appeared to be a galaxy nearby, about 120,000 light years away.
Telescope observations suggest that neutron stars have been expelled from the nearby galaxy. They probably formed as a pair of massive stars in a binary system. Eventually, both stars collapsed into neutron stars, in powerful events that effectively “expelled” the pair from their home galaxy, causing them to escape to a new location where they slowly circled around each other and merged, several hundred million years later.
Amid the energetic emissions from the fusion, JWST also detected a clear signal of tellurium. While most stars can produce lighter elements up to iron, all the other heavier elements in the universe are believed to have been forged in more extreme environments, such as a neutron star merger. Tellurium detection by JWST further confirmed that the initial gamma-ray burst was produced by a neutron star merger.
“For JWST, it’s just the beginning and it’s already made a huge difference,” says Schneider. “In the coming years, more neutron star mergers will be detected. Combining JWST with other powerful observatories will be crucial in clarifying the nature of these extreme explosions.”
For more information about this research, see:
Reference: “Production of heavy elements in a merger of compact objects observed by JWST” by Andrew Levan, Benjamin P. Gompertz, Om Sharan Salafia, Mattia Bulla, Eric Burns, Kenta Hotokezaka, Luca Izzo, Gavin P. Lamb , Daniele B. Malesani, Samantha R. Oates, Maria Edvige Ravasio, Alicia Rouco Escorial, Benjamin Schneider, Nikhil Sarin, Steve Schulze, Nial R. Tanvir, Kendall Ackley, Gemma Anderson, Gabriel B. Brammer, Lise Christensen, Vikram S. Dhillon, Phil A. Evans, Michael Fausnaugh, Wen-fai Fong, Andrew S. Fruchter, Chris Fryer, Johan PU Fynbo, Nicola Gaspari, Kasper E. Heintz, Jens Hjorth, Jamie A. Kennea, Mark R. Kennedy, Tanmoy Laskar , Giorgos Leloudas, Ilya Mandel , Antonio Martin-Carrillo, Brian D. Metzger, Matt Nicholl, Anya Nugent, Jesse T. Palmerio, Giovanna Pugliese, Jillian Rastinejad, Lauren Rhodes, Andrea Rossi, Andrea Saccardi, Stephen J. Smartt, Heloise F . Stevance, Aaron Tohuvavohu, Alexander van der Horst, Susanna D. Vergani, Darach Watson, Thomas Barclay, Kornpob Bhirombhakdi, Elmé Breedt, Alice A. Breeveld, Alexander J. Brown, Sergio Campana, Ashley A. Chrimes, Paolo D’Avanzo , Valerio D’Elia, Massimiliano De Pasquale, Martin J. Dyer, Duncan K. Galloway, James A. Garbutt, Matthew J. Green, Dieter H. Hartmann, Páll Jakobsson, Paul Kerry, Chryssa Kouveliotou, Danial Langeroodi, Emeric Le Floc ‘h, James K. Leung, Stuart P. Littlefair, James Munday, Paul O’Brien, Steven G. Parsons, Ingrid Pelisoli, David I. Sahman, Ruben Salvaterra, Boris Sbarufatti, Danny Steeghs, Gianpiero Tagliaferri, Christina C. Thöne , Antonio de Ugarte Postigo and David Alexander Kann, October 25, 2023, Nature.