Learn more about supernovae through stardust

Most of the diverse elements in the universe are born from supernovae. We are literally made from the dust of long-dead stars and other astrophysical processes. But the details of how that happens are what astronomers are still trying to understand.

How do the different isotopes produced by supernovae drive the evolution of planetary systems? Of the different types of supernovae, supernovae are the most responsible for producing the elemental abundances we see today. Which one plays a role? One way astronomers can study these questions is by observing presolar particles.

These are dust particles that formed long before the Sun was formed. Some of them were driven out of old systems as stars fired up nuclear reactors and cleared the systems of dust. Some are formed from the remains of supernovae or stellar collisions. Regardless of its origin, each presolar particle has a unique isotopic fingerprint that tells its story.

For decades, we were only able to study presolar particles in meteorites, but missions such as Stardust have captured particles from comets, providing a richer source for research. . Observations with radio telescopes such as ALMA allow astronomers to study the isotope ratios of these particles at their origin. We can now study presolar particles both in the laboratory and in space.

A new study posted on the arXiv preprint server compares the two, focusing on the role of supernovae.

What they discovered was that the physical collection of presolar particles is important for understanding their origins. For example, Type II supernovae, also known as nuclear collapse supernovae, are known to produce the unstable isotope titanium-44. Through the decay process, excess calcium-44 can be produced within the presolar particles.

However, grains released from young star systems also contain excess calcium-44. In the former case, the particles are formed of titanium and then disintegrate into calcium, whereas in the latter case, the particles are formed directly with calcium. You cannot tell the two apart just by looking at the isotope ratio. Instead, we should focus on the specific distribution of calcium 44 within the grain.

Researchers have discovered that nanoscale secondary ion mass spectrometry (NanoSIMS) can be used to identify the origin of particles found in meteorites. Similar complexities are found in silicon and chromium isotopes.

Overall, this study proves that more work is needed to unravel the origins of the presolar particles we collected. But as we learn more about the particles we collect here on Earth, it should help us uncover a deeper understanding of how elements are forged in the nuclear reactors of large stars.