'Our galaxy is a beautiful melting pot of stars,' said Alejandra Recio-Blanco of the Observatoire de la Côte d’Azur in France, who is a member of the Gaia collaboration. Gaia also identified stars that originally came from different galaxies than our own, based on their chemical composition. Stars that are closer to the centre and plane of our galaxy are richer in metals than stars at larger distances. With Gaia, experts can 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. 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.Īctive star formation and death will lead to an environment that is richer in metals, so a star's chemical composition is a bit like its DNA, giving astronomers crucial information about its origin. Some stars contain more 'heavy metals' than others.ĭuring the Big Bang, only light elements were formed (hydrogen and helium). All other heavier elements – called metals by astronomers – are built inside stars. With its third data release, Gaia has revealed the largest chemical map of the galaxy coupled to 3D motions, from our solar neigbourhood to smaller galaxies surrounding ours. What stars are made of can tell us about their birthplace and their journey afterwards, and therefore about the history of the Milky Way. Gaia is opening a goldmine for "asteroseismology" of massive stars,' said Conny Aerts of KU Leuven in Belgium, who is a member of the Gaia collaboration. 'Starquakes teach us a lot about stars, notably their internal workings. These non-radial oscillations change the global shape of a star and are therefore harder to detect. Previously, Gaia had found radial oscillations that cause stars to swell and shrink periodically, while keeping their spherical shape.īut Gaia has now also spotted other vibrations that astronomers described as being 'more like large-scale tsunamis'. One of the most surprising discoveries to emerge from the new data was that Gaia was able to detect starquakes – tiny motions on the surface of a star – that change the shapes of stars, something the observatory was not originally built for. The map provides the largest ever catalogue of information on stars in the Milky Way, including their chemical compositions, stellar temperatures, colours, masses, ages, and the speed at which stars move towards or away from us (radial velocity). We can take measurements of them to work out all the physical properties of the system, such as the stars' masses and sizes, and how far away they are. This is especially true for eclipsing binary systems, which are lined up so that the stars pass in front of each other from our point of view. It has just revealed new measurements of 156,000 known asteroids, telling us exactly what paths they follow as they orbit the sun.īinary stars which orbit each other around a shared centre can tell us a lot about how stars work and how they are formed. They let us measure the distance to the furthest reaches of the universe, which in turn lets us measure how quickly the universe is expanding.Ī few hundred asteroids with moons are already known, but Gaia can find asteroid moons even when the moon is too small to see directly.
The new data includes measurements of 1.1 million quasars - the most luminous objects in the universe and the most distant objects we can see. Gaia could tell us more about old stars that are reaching the ends of their lives - some of which could go on to produce supernovas eventually.ģ. This means we now have not only the best map of where the galaxy’s stars are now, but we can track their motions forward to see how things will change, and backward to see how things used to be. It reveals how quickly stars are moving away from us or towards us, something we call the stars' radial velocities. The latest release of data contains the largest three-dimensional map of the Milky Way ever produced - showing how the stars in our galaxy are travelling. The European Space Agency's Gaia satellite, which was launched in 2013, has just released new data that unveils 'starquakes' and a 'DNA' map of 2 billion stars. Here are five insights that the data might also provide:Įverything in space is moving, and the stars are no exception.