First statement of a star’s inside opens unprecedented window into the start of matter | Science

“The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff,” proclaimed American astrophysicist Carl Sagan in his well-known ebook Cosmos nearly half a century in the past. A staff of scientists has now been in a position to peer into these stellar bowels for the primary time, the chaotic forge the place the chemical parts that make up human beings and every part round them are shaped. “I was dazzled,” remembers German astrophysicist Steve Schulze, who led the analysis.

To perceive the importance of this discovery, we should return to the Big Bang that gave rise to the universe 13.8 billion years in the past. In the primary three minutes after the Big Bang, nearly all the universe’s mild atoms have been shaped, particularly the ever-present hydrogen, the accumulations of which type stars. In the inside of a star, the temperature and stress are so excessive that hydrogen fuses and kinds more and more heavier parts, beginning with helium. The mixture of silicon and sulfur, for instance, produces iron, the heaviest atom that may be generated inside a star.

The result’s a type of “cosmic onion,” a time period generally utilized by astronomers. “This process transforms the star into a layered structure: hydrogen on the outside, then helium, then layers of carbon/oxygen, magnesium/neon/oxygen, oxygen/silicon/sulfur, and finally iron in the center. Therefore, the silicon- and sulfur-rich layer is buried beneath many other materials and is inaccessible under normal circumstances, making it almost impossible to observe directly,” notes Schulze, of Northwestern University in Evanston, Texas.

In September 2021, a telescope situated on the summit of a Hawaiian volcano recorded the spectrum of sunshine emitted by a supernova, the explosion of a star. The explosion, which occurred 2.2 billion light-years away and was referred to as SN 2021yfj, was not simply one other supernova. The machine captured the phenomenon at a rare second, simply because the star was stripping away its outer layers, permitting a glimpse into its inside. “At first, we didn’t know we had discovered a star stripped to the bone. I was astounded when Professor Avishay Gal-Yam of the Weizmann Institute of Science [in Israel] concluded that we had observed silicon, sulfur, and argon,” Schulze remembers. His discovery was revealed Wednesday on the cover of the journal Nature, a number one worldwide science publication.

Schulze, born in Halle, Germany 45 years in the past, emphasizes that “more than one billion stars” are identified within the Milky Way galaxy wherein Earth is situated and in its neighboring Magellanic Clouds. Most of those stars retain their hydrogen layer upon loss of life, however a minority lose this layer and even the deeper helium layer earlier than exploding right into a supernova. This floor stripping can happen because of robust stellar winds, eruptions, or interactions with one other star, however a just about full stellar stripping has by no means been detected.

“No star in the Milky Way or the Magellanic Clouds is known to be stripped down to the oxygen/silicon layer. The discovery of supernova SN 2021yfj indicates that rare and very extreme stripping processes exist,” argues Schulze, who labored on the Institute of Astrophysics on the Pontifical Catholic University of Chile till a decade in the past. The fusion of chemical parts heavier than carbon solely happens in stars which are no less than eight instances the mass of the Sun, incomes them the designation huge. “This is the first time we have observed the inner layers of a massive star, which is important for testing and improving our models of stellar evolution. Furthermore, this discovery provides us with information about the formation of silicon and sulfur in massive stars,” provides Schulze.

The German astrophysicist’s clarification echoes one other comparable thought by Sagan, this time from his tv sequence Cosmos: “The silicon in the rocks, the oxygen in the air, the carbon in our DNA, the gold in our banks, the uranium in our arsenals, were all made thousands of light years away and billions of years ago. Our planet, our society, and we ourselves are built of star stuff.”

Physicist José Ángel Martín Gago’s staff has constructed a €4 million machine in his laboratory to simulate the loss of life of stars on the Institute of Materials Science in Madrid. Martín Gago and his colleague Gonzalo Santoro, from the Institute of Fundamental Physics, rejoice the brand new discovery in a joint evaluation despatched to this newspaper. “This observation confirms the layered structure of supernovae, which is the model that has been used to describe them, although until now it was not clear whether it was valid. Confirming this model is very important for describing stellar evolution,” they state.

Supernovae and pink large stars are important objects within the formation of cosmic mud, the 2 Spanish researchers emphasize. “This study provides fundamental information for understanding how chemical species form and evolve in the universe. At the level of laboratory astrochemistry, this work opens new avenues, as it provides empirical values for the abundances of silicon and sulfur that could be used to recreate in the laboratory the conditions for the formation and evolution of molecules rich in these elements,” they clarify. “This approach will allow progress in the modeling of chemical reactions and a deeper understanding of the processes of cosmic dust formation in space,” they add. The discovery of the bare star presents an unprecedented window into the creation of the stellar substance from which people and every part else are made.

Sign up for our weekly newsletter to get extra English-language information protection from EL PAÍS USA Edition