Astronomers have uncovered the most detailed study of the Milky Way, which reveals thousands of “star tremors” and stellar DNA and helps identify the most habitable corners of our home galaxy.
Observations from the European Space Agency’s Gaia spacecraft cover nearly two billion stars – about 1% of the galaxy’s total – and allow astronomers to reconstruct the structure of our home galaxy and understand how it evolved over billions of years.
Previous studies of Gaia, a robotic spacecraft launched in 2013, have shown the movement of stars in our home galaxy with exquisite detail. By scrolling through these movements, astronomers can model how our galaxy has changed over time. Recent observations add details of chemical composition, stellar temperatures, colors, masses, and age based on spectroscopy, where stellar light is split into different wavelengths.
These measurements unexpectedly revealed thousands of stellar tremors, cataclysmic events similar to tsunamis on the surface of stars. “Star earthquakes teach us a lot about the stars – especially their inner workings,” said Connie Arts of KU Leuven in Belgium, a member of the Gaia collaboration. “Gaia opens a gold mine for asteroseismology of massive stars.”
Dr George Seabrook, a senior fellow at the Mullard Space Science Laboratory at University College London, said: “If you could see these stars change brightness in the middle of the Milky Way, if you were anywhere near them, it would be like the sun changing its shape before your eyes. ”
Gaia is equipped with a 1 billion pixel camera – the largest in space – complete with more than 100 electronic detectors. The latest dataset is the largest chemical map of the galaxy to date, cataloging the composition of six million stars, ten times the number measured in previous terrestrial catalogs.
What the stars are made of can tell us about their birthplace and their journey thereafter and help us unravel the history of the Milky Way. The first primary stars, formed shortly after the Big Bang, had only light elements available – hydrogen and helium. They produced the first supernovae that enriched galaxies with metals and elements such as carbon and oxygen, and successive generations of stars made more heavy elements available. The chemical composition of the star bears little resemblance to its DNA, which gives us important information about its origin.
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Gaia revealed that some stars in our galaxy are made of primary material, while others like our Sun are made of matter enriched by previous generations of stars. Stars that are closer to the center and plane of our galaxy are richer in metals than stars at greater distances. Gaia also identifies stars that originally came from different galaxies than ours, based on their chemical composition.
“Our galaxy is a beautiful melting pot of stars,” said Alejandra Resio-Blanco of the Cote d’Azur Observatory in France, a member of the Gaia Collaboration. “This diversity is extremely important because it tells us the story of the formation of our galaxy.”
Seabrook said tracing the “gradient of metallicity” across the galaxy could help identify habitable regions of the Milky Way. “If the sun were born in a region with much higher metal content, there would be many more supernovae that would pose a risk to life on Earth,” he said.
The title of this article was changed on June 13, 2022. The original version refers to DNA “stela”. The correct spelling is “star”.
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