A team of scientists have made an important discovery! They found that most stars in the universe are enriched by multiple supernovae, thanks to modern machine learning and best-in-class research. This result was published in a journal called The Astrophysical Journal.
We know from research in nuclear astrophysics that elements from carbon and up in the Universe are made by stars. But the first stars which formed after the Big Bang didn’t contain those heavier elements, which we call “metals”. The next batch of stars only had small amounts of these metals, created by the first ones. To figure out what was happening back then, scientists need to look into these metal-poor stars.
We are very lucky as we can observe second-generation stars that have a low metal content in our Milky Way Galaxy. Scientists who belong to the Kavli Institute for the Physics and Mathematics of the Universe have studied these stars, so we know more about what the first stars in the universe were like.
A team of scientists led by Tilman Hartwig and including Miho Ishigaki, Chiaki Kobayashi, Nozomu Tominaga, and Ken’ichi Nomoto utilized artificial intelligence to analyze the chemical components found in more than 450 stars that were called ‘extremely metal-poor stars’. With the help of a machine learning algorithm based on theoretical models they discovered that 68 percent of these stars had been changed earlier by some type of explosion coming from supernovae.
The team’s findings have given us a number that tells us about how many stars first appeared in the beginning.
Scientists have been predicting that the first stars created in the universe formed together in groups, but no one was certain until now. This new result suggests that most of these first stars probably did come together to form small clusters, which could be seen as multiple exploding supernovae at once. That event would lead to metals and gas being scattered around space.
Kobayashi, who is part of a research fellowship, announced that they created a new algorithm which will help us dig through an extremely large amount of data that we’re going to get from future and current astronomical observations across the globe.
We have only found a small part of the old stars close to our Solar System. The Prime Focus Spectrograph can help us see much further away and discover lots of them. This amazing tool is installed on Subaru Telescope which was made by an international team lead by Kavli IPMU, as explained by Ishigaki.
Scientists have come up with a new way to use unique chemical signatures in certain stars discovered by the Prime Focus Spectrograph.
Scientists once thought the first stars ever made were more massive than our Sun and would have been born in a cloud of gas that was a million times bigger. But now, it looks like the first stars probably weren’t alone – they formed together in clusters or as part of double or multiple star systems! This means we might be able to detect rUMBLes from those very old stars sooner than we thought, by sending spacecrafts into space or even on the moon.
Hartwig has put the code used in his research online for everyone to use. You can find it easily at https://gitlab.com/thartwig/emu-c. It was part of a study called “Machine Learning Detects Multiplicity of the First Stars in Stellar Archaeology Data” by Tilman Hartwig, Miho N. Ishigaki, Chiaki Kobayashi, Nozomu Tominaga and Ken’ichi Nomoto which was published in The Astrophysical Journal on 22 March 2023 with the DOI: 10.3847/1538-4357/acbcc6.
