ESA unveils its third Milky Way data catalog

This new dataset notably includes finer details of nearly two billion stars in the galaxy. Chemical compositions, stellar temperatures, colors, masses, ages and the speed at which stars approach or move away from the earth, are all new information obtained thanks to spectroscopy, a technique which uses the luminous spectrum of stellar light.

The data also revealed Gaia’s ability to detect stellar quakes, tiny movements on the surface of a star that change its shape, something the satellite was not originally designed for. “Starquakes tell us a lot about stars, including their inner workings. Gaia opens up a gold mine for the ‘asteroseismology’ of massive stars,” explains Conny Aerts, from KU Leuven, a member of the Gaia collaboration.

The satellite has also made it possible to learn more about the chemical composition of stars, which makes it possible to obtain information on “their place of birth and their journey thereafter, therefore on the history of the Milky Way”. The catalog published on Monday therefore offers the largest chemical map of the galaxy. “The chemical composition of a star is a bit like its DNA, giving us crucial information about its origin,” says ESA. “With Gaia, we see that some stars in our galaxy are made up of primordial matter, while others like our Sun are made up of matter enriched by previous generations of stars. Stars closer to the center and plane of our galaxy are richer in metals than stars at greater distances. »

This new set also contains the largest catalog to date of binary stars, thousands of solar system objects such as asteroids and satellites of planets. This presents the orbital characteristics of more than 800,000 binary systems, as well as a new study of asteroids comprising 156,000 rocky bodies. Gaia further reveals information about “10 million variable stars, mysterious macromolecules between stars, as well as quasars and galaxies beyond our own cosmic neighborhood.”

Launched in December 2013 by ESA, the Gaia satellite aims to map part of our galaxy. In particular by identifying nearly a billion celestial objects (stars, exoplanets?), by estimating the distance which separates them from the earth as well as their own speed. With these observations, astronomers hope to shed light on the formation, structure and history of the Milky Way.

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