Half of the calcium in the universe, including in our teeth and bones, is made up of the “last breath” of dying stars.
This kind of so-called “calcium-rich supernova” is particularly rare and elusive. Over the past year, astronomers have spent a lot of efforts to find and research, to decode their nature and mechanism of calcium formation.
In a new study led by Northwestern University in the US, scientists have examined calcium-rich supernovae for the first time with X-rays, providing an unprecedented view of dying stars.
Simulate a calcium-rich supernova explosion. Graphics: Aaron M. Geller.
The new discovery reveals the nature of calcium-rich supernovae as small stars emitting gas around them during the final stages of their life cycle. When it explodes, the star’s matter collides with the loose outer gas and emits bright X-rays. The event causes the temperature and pressure to skyrocket, leading to chemical reactions that form calcium.
Although rare, such explosions contribute up to 50% of the calcium in the universe. While typical stars make only small amounts of calcium through helium burning throughout their lifecycle, calcium-rich supernovae release large amounts of this element in seconds.
By observing the X-rays emitted from the star during the last month of their life, the scientists looked into a place that had never been previously discovered, opening a new path to research into this mysterious event. .
“In the past, we had speculations about what might or might not happen in calcium-rich supernovae. Now, we can confidently rule out some possibilities,” said Raffaella Margutti, a researcher. Professor of physics and astronomy at Northwestern University, said the lead author of the study.
The calcium-rich supernova event was first observed on April 28, 2019. Amateur astronomer Joel Shepherd stumbled upon the explosion – known as SN2019ehk – while observing the spiral galaxy Messier 100 55 million light years away with a new telescope.
Position of SN2019ehk in the galaxy Messier 100. Photo: Hubble Space Telescope.
Shortly after the existence of a potential supernova within the Messier 100, a global collaborative project was activated with the participation of nearly 70 senior astronomers from 15 countries.
Based on observations from the world’s leading telescopes systems such as NASA’s Swift satellite, WM Keck Observatory in Hawaii and Lick Observatory in California, USA, scientists emphasize that the SN2019ehk explosion was single astrophysical event that released the most calcium ever known.
Details of the study were published in the Astrophysical Journal on August 5.