- Gaia is an ESA mission whose goal is to create the most complete multidimensional map of the Milky Way.
- Gaia's third data release includes new and improved information on two billion stars.
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| The data includes special subsets of stars, such as those that change brightness over time. / Pixabay |
ESA's Gaia mission releases its new trove of data about our galaxy on Monday. In this detailed study of the Milky Way, astronomers have described unusual "stellar earthquakes", stellar DNA, asymmetric motions, and other fascinating data.
Gaia is an ESA mission that aims to create the most accurate and complete multi-dimensional map of the Milky Way. This allows astronomers to reconstruct the structure and past evolution of our galaxy over billions of years, as well as better understand the life cycle of stars and our place in the Universe.
Gaia's third data release includes new and improved information on nearly two billion stars in our galaxy. The catalog incorporates new information, including chemical compositions, temperatures, colors, masses, ages, and the speed at which stars are moving toward or away from us (radial velocity).
Much of this information comes from new spectroscopy data now published, a technique in which starlight is split into its component colors (like a rainbow). Also, the data includes special subsets of stars, such as those that change brightness over time.
Also new to this dataset is the largest catalog to date of binary stars, thousands of Solar System objects such as asteroids and the moons of planets, and millions of galaxies and quasars outside the Milky Way.
Stellar earthquakes
One of the most surprising discoveries made from these new data is that Gaia can detect stellar earthquakes (small movements recorded on the surface of a star) that change the shape of stars, something the observatory was not originally set to detect. had designed.
Gaia had previously found radial oscillations that caused stars to periodically grow larger and smaller while maintaining their spherical shape. But now Gaia has also detected other vibrations that can be considered large-scale tsunamis. These non-radial oscillations alter the overall shape of the star and are therefore more difficult to detect.
Gaia has discovered powerful non-radial stellar quakes in thousands of stars. Gaia has also detected these vibrations in stars where they have rarely been seen before. Although these stars should not register any earthquakes according to current theory, Gaia has detected them on its surface.
"Starquakes give us a lot of information about stars, especially their inner workings. Gaia opens up a gold mine for asteroseismology of massive stars," said Conny Aerts of Ku Leuven in Belgium, a member of the Gaia Collaboration.
The DNA of the stars
The composition of stars can tell us about their place of birth and subsequent trajectory, and thus about the history of the Milky Way. With the data release, Gaia presents the largest chemical map of the Galaxy along with 3D motions, ranging from the solar neighborhood to the smaller galaxies that surround it.
Some stars contain more "heavy metals" than others. During the Big Bang, only light elements (hydrogen and helium) were formed. The rest of the heavier elements—called metals by astronomers—are created inside stars. When stars die, they release these metals into the gas and dust between stars, called the interstellar medium, from which new stars form. The active formation of stars and their death allows for the existence of an environment richer in metals. Therefore, the chemical composition of a star is like its DNA and offers crucial information about its origin.
"Gaia inaugurates a gold mine for asteroseismology of massive stars"
Thanks to Gaia, it has been observed that some stars in this galaxy are composed of primordial material, while others, like the Sun, contain enriched matter from previous generations of stars. Stars closer to the center and plane of this galaxy are richer in metals compared to stars further away. Gaia has also identified stars that originally came from galaxies other than our own, based on their chemical composition.
"Our galaxy is a beautiful melting pot of stars," said Alejandra Recio-Blanco, a member of the Gaia Collaboration at the Observatoire de la Côte d'Azur in France.
"This diversity is extremely important as it tells us the story of the formation of our galaxy. It reveals the migration processes within our galaxy and the accretion of external galaxies. It also clearly shows that our Sun and all of us belong to one system. in continuous change, formed thanks to the meeting of stars and gas coming from different origins".
Binary stars, asteroids, and quasars
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| Milky Way / GAIA |