Supernova core found to contain silicon and sulfur.

An international research team led by scientists from the Weizmann Institute of Science (Israel) and Northwestern University (USA) has discovered that the core of a supernova – a massive exploding star – contains many heavy elements such as silicon, sulfur, and argon.

This was the first time scientists had directly observed this structure before the explosion occurred.

The star, named SN2021yfj, unexpectedly lost its outer layers, revealing a blazing core at the center – believed to be the star's "heart" – before exploding.

Professor Avishay Gal-Yam, head of the experimental astrophysics group at the Weizmann Institute, said: "We now have evidence that heavy elements exist inside stars. We know the Sun is mostly hydrogen and we've hypothesized that stars contain heavier elements. But this is the first time we've proven it."

In addition to Professor Gal-Yam, the research also involved Dr. Ofer Yaron, a leading expert on supernova databases at the Weizmann Institute, and Dr. Steve Schulze, the lead author of the work, currently a researcher at Northwestern University (formerly a member of Gal-Yam's team). The research team also included scientists from France, Italy, China, and Ireland.

The star SN2021yfj was first discovered in September 2021 through the Zwicky Transient Facility Observatory in California (USA), using a wide-angle camera to scan the entire night sky.

Dr. Schulze discovered an unusual burst of light in a star-forming region 2.2 billion light-years from Earth.

To determine the elemental composition precisely, the research team sought to collect light spectra—a light analysis technique—to identify the elements present in the explosion.

However, due to weather conditions and a lack of suitable observation equipment, it took some time for the team to obtain spectral data from a colleague at the University of California, Berkeley.

Immediately after receiving the data, Professor Gal-Yam identified the presence of silicon, sulfur, and argon—qualities never before recorded.

Typically, supernovae form when a massive star, nearing the end of its life, collapses due to its own gravity, causing a powerful explosion and emitting light that lasts for weeks.

Previously, "stripped stars" were typically observed to expose only layers of helium or carbon and oxygen after losing their outer hydrogen shell.

However, SN2021yfj has lost more layers, allowing scientists to observe deeper into the core and discover heavy elements never before recorded before the explosion.

Dr. Schulze said: "This star lost most of the matter it created during its lifetime. We were only able to observe the matter that formed in the months before it exploded. There must have been some kind of violent upheaval."

Scientists hypothesize that the supernova explosion may have been influenced by a companion star, a proto-supernova eruption, or even strong, unusual stellar winds.

Professor Gal-Yam emphasized: "Looking deep into the core of a giant star expands our scientific understanding of the origins of heavy elements. Every atom in our bodies and in the world around us was formed somewhere in the universe. They undergo countless transformations over billions of years before they arrive here, so tracing their origins and formation processes is a huge challenge."

Professor Gal-Yam's research team said they will continue to pursue studies to further explore how elements form in the universe.

(Vietnam+)

Source: https://www.vietnamplus.vn/phat-hien-loi-sieu-tan-tinh-chua-silic-va-luu-huynh-post1056999.vnp