“Why are we here?” stays one of the vital enduring questions humans have posed. A technique scientists approach this concept is by tracing where the weather around us first formed. Many elements are created inside stars and within the explosive debris of supernovae, which scatter this material across space, however the origins of several vital elements have been difficult to elucidate.
Chlorine and potassium fall into this category. They’re classified as odd-Z elements — possessing an odd variety of protons — and are crucial for each life and the event of planets. Current models, nonetheless, indicate that stars should produce only about one-tenth of the chlorine and potassium that astronomers actually observe within the universe, resulting in a long-standing scientific puzzle.
XRISM Offers a Latest Method to Study Supernova Debris
This gap in understanding led researchers at Kyoto University and Meiji University to research whether supernova remnants might hold the missing clues. They used XRISM — short for X-Ray Imaging and Spectroscopy Mission, an X-ray satellite launched by JAXA in 2023 — to collect high-resolution X-ray spectroscopic data from the Cassiopeia A supernova remnant within the Milky Way.
To perform this, the team relied on the microcalorimeter Resolve instrument on XRISM. The device provides energy resolution roughly ten times sharper than earlier X-ray detectors, which allowed the researchers to select up faint emission lines related to rare elements. After collecting the information from Cassiopeia A, they compared the measured amounts of chlorine and potassium with several theoretical models of how supernovae create elements.
Evidence That Supernovae Produce Life-Related Elements
The outcomes showed clear X-ray emission lines of each chlorine and potassium at levels far higher than expected from standard models. This marks the primary observational confirmation that a single supernova can generate enough of those elements to match what astronomers see within the cosmos. The researchers consider that strong internal mixing inside massive stars, possibly driven by rapid rotation, binary interactions, or shell-merger events, can greatly increase the production of those elements.
“After we saw the Resolve data for the primary time, we detected elements I never expected to see before the launch. Making such a discovery with a satellite we developed is a real joy as a researcher,” says corresponding writer Toshiki Sato.
Insights Into How Stars Shape the Constructing Blocks of Life
These findings show that the chemical ingredients essential for all times formed under extreme conditions deep inside stars, far faraway from anything resembling the environments where life later emerged. The work also demonstrates how powerful high-precision X-ray spectroscopy has turn out to be in uncovering the processes at work inside stellar interiors.
“I’m delighted that we have now been able, even when only barely, to start to know what is occurring inside exploding stars,” says corresponding writer Hiroyuki Uchida.
Next Steps for Understanding Stellar Evolution
The team plans to proceed studying additional supernova remnants with XRISM to find out whether the elevated levels of chlorine and potassium present in Cassiopeia A are typical of massive stars or unique to this particular remnant. This can help reveal whether the inner mixing processes identified listed here are a widespread feature of stellar evolution.
“How Earth and life got here into existence is an everlasting query that everybody has pondered at the very least once. Our study reveals only a small a part of that vast story, but I feel truly honored to have contributed to it,” says corresponding writer Kai Matsunaga.