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Gaia sees strange stars in most detailed Milky Way survey to date by Staff Writers Paris (ESA) Jun 14, 2022
Today, ESA's Gaia mission releases its new treasure trove of data about our home galaxy. Astronomers describe strange 'starquakes', stellar DNA, asymmetric motions and other fascinating insights in this most detailed Milky Way survey to date. Gaia is ESA's mission to create the most accurate and complete multi-dimensional map of the Milky Way. This allows astronomers to reconstruct our home galaxy's structure and past evolution over billions of years, and to better understand the lifecycle of stars and our place in the Universe.
What's new in data release 3? Also new in this data set is the largest catalogue yet of binary stars, thousands of Solar System objects such as asteroids and moons of planets, and millions of galaxies and quasars outside the Milky Way.
Starquakes Previously, Gaia already found radial oscillations that cause stars to swell and shrink periodically, while keeping their spherical shape. But Gaia has now also spotted other vibrations that are more like large-scale tsunamis. These nonradial oscillations change the global shape of a star and are therefore harder to detect. Gaia found strong nonradial starquakes in thousands of stars. Gaia also revealed such vibrations in stars that have seldomly been seen before. These stars should not have any quakes according to the current theory, while Gaia did detect them at their surface. "Starquakes teach us a lot about stars, notably their internal workings. Gaia is opening a goldmine for 'asteroseismology' of massive stars," says Conny Aerts of KU Leuven in Belgium, who is a member of the Gaia collaboration.
The DNA of stars Some stars contain more 'heavy metals' than others. During the Big Bang, only light elements were formed (hydrogen and helium). All other heavier elements - called metals by astronomers - are built inside stars. When stars die, they release these metals into the gas and dust between the stars called the interstellar medium, out of which new stars form. Active star formation and death will lead to an environment that is richer in metals. Therefore, a star's chemical composition is a bit like its DNA, giving us crucial information about its origin. With Gaia, we see that some stars in our galaxy are made of primordial material, while others like our Sun are made of matter enriched by previous generations of stars. Stars that are closer to the centre and plane of our galaxy are richer in metals than stars at larger distances. Gaia also identified stars that originally came from different galaxies than our own, based on their chemical composition. "Our galaxy is a beautiful melting pot of stars," says Alejandra Recio-Blanco of the Observatoire de la Cote d'Azur in France, who is a member of the Gaia collaboration. "This diversity is extremely important, because it tells us the story of our galaxy's formation. It reveals the processes of migration within our galaxy and accretion from external galaxies. It also clearly shows that our Sun, and we, all belong to an ever changing system, formed thanks to the assembly of stars and gas of different origins."
Binary stars, asteroids, quasars, and more "Unlike other missions that target specific objects, Gaia is a survey mission. This means that while surveying the entire sky with billions of stars multiple times, Gaia is bound to make discoveries that other more dedicated missions would miss. This is one of its strengths, and we can't wait for the astronomy community to dive into our new data to find out even more about our galaxy and its surroundings than we could've imagined," says Timo Prusti, Project Scientist for Gaia at ESA. More details on Gaia's data releases 3 can be found here
Research Report:Series of scientific papers at Astronomy and Astrophysics
Astronomers find 'gold standard' star in Milky Way Ann Arbor MI (SPX) May 12, 2022 In our sun's neighborhood of the Milky Way Galaxy is a relatively bright star, and in it, astronomers have been able to identify the widest range of elements in a star beyond our solar system yet. The study, led by University of Michigan astronomer Ian Roederer, has identified 65 elements in the star, HD 222925. Forty-two of the elements identified are heavy elements that are listed along the bottom of the periodic table of elements. Identifying these elements in a single star will help astr ... read more
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