Researchers, including one of Indian-origin, have described oxygen's different shapes and found how the element's nuclear shape changes depending on its state.
Oxygen-16, one of the key elements of life on Earth, is produced by a series of reactions inside of red giant stars.
Researchers have showed how the element's nuclear shape changes depending on its state, even though other attributes such as spin and parity don't appear to differ.
The findings may shed light on how oxygen is produced.
Carbon and oxygen are formed when helium burns inside of red giant stars. Carbon-12 forms when three helium-4 nuclei combine in a very specific way (called the triple alpha process), and oxygen-16 is the combination of a carbon-12 and another helium-4 nucleus.
Although physicists knew what oxygen-16 was made of, they were still puzzled by the fact that both the ground and first excited states of the element had zero spin and positive parity.
At room temperature, only the ground state of oxygen-16 is seen due to the very cold temperature compared to nuclear energies.
But the excited states of oxygen-16 become important for the helium-burning reactions inside stars.
"It's expected that oxygen-16 would have zero spin and positive parity as its ground state," said Dean Lee from North Carolina State University, co-author of the research paper.
Lee and colleagues had previously developed a new method for describing all the possible ways that protons and neutrons can bind with one another inside nuclei such as carbon-12 and the Hoyle state.
They used an approach called "effective field theory" formulated on a complex numerical lattice that allows the researchers to run simulations that show how particles interact, and so reveal the structure of the nuclei.
In this work, the same team plus Mississippi State University physicist Gautam Rupak, found their lattice revealed that although both the ground and first excited states of oxygen-16 "look" the same in terms of spin and parity, they are in fact quite different structurally.
The results appear in the journal Physical Review Letters.
