Space: Gaia draws an unprecedented map of the Satellite Milky Way

The Space Telescope, located 1.5 million kilometers away from the Earth opposite the Sun, is part of its third data collection, aimed at mapping our galaxy at all its dimensions and thus understanding its origin, structure and dynamics.

Astronomers are turning heads: The Gaia Space Telescope on Monday, June 13, provided its new data on nearly two billion stars in the Milky Way, with incredible precision that makes it possible to draw a map of our galaxy, bubbling with life.

“This is a wonderful day for astronomy, which opens the floodgate to new discoveries about the universe and our galaxies,” said Joseph Ashbacher, director general of the European Space Agency (ESA), who launched the mission in 2013.

Equipped with two telescopes and a billion pixel photographic sensor, Gaia scans a very small fraction (only 1%) of the stars in our galaxy, measuring 100,000 light-years in diameter.

The figures unveiled on Monday are incomprehensible: analyzing 700 million data sent to Earth every day, over a period of 34 months, Gaia was able to provide information on more than 1.8 billion stars.

“Patachan Life”

A host of unprecedented details, such as these 220 million photometric spectra, have been provided, which will make it possible to estimate the mass, color, temperature and age of stars for the first time. And 2.5 million new chemical combinations, this “DNA” informs about the birthplace of stars and their journey through galaxies. Or 35 million radial velocities, which measure the displacement of stars and offer a new understanding of the motion of the Milky Way.

Wonders for Scientists: For the first time, Gaia observed a “vibration” of a star, a tiny movement on the surface of a star that changes its shape. The discovery opens up “a gold mine for the asterosismology of the giant stars,” as Connie Arts of the University of Louvain (Belgium) explains, in their internal work, a member of the Gaia collaboration.

“At all levels, Gaia has exceeded expectations,” welcomed Franোয়াois Mignard, scientific manager of the Gaia Mission in France. The results, which have given rise to nearly fifty scientific articles in the process, are drawing “much more turbulent” than expected from a galaxy portrait, astronomers from the C ডিte d’Azur Observatory added.

“We thought it had reached a steady state, slowly turning itself on, like a liquid that gently shakes with a wooden spoon. But not at all!”, Further developed Francois Mignard. Accidents, in contrast to his “Patacon’s life”, are made up of unexpected movements and this spiral is not as simple as he described. For example, our solar system “does not just rotate in a vertical plane, it goes up and down, up and down,” Says.

It is home to a very diverse population of stars, some of which have not been there since the beginning but may have been “swallowed” along the way by interacting with nearby Sagittarius dwarf galaxies.

“Star Crucible”

“Our galaxy is a great melting pot of stars,” summarizes Alejandra Resio-Blanco of the Cote d’Azur Observatory. The level of accuracy of Gaia is such that it would “allow us to explore the galaxy’s past for more than 10 billion years,” added Anthony Brown, president of the international consortium DPAC, the ground processing chain of data streams transmitted by Gaia. .

The stars have the peculiarity of living for billions of years: their analysis is equivalent to the study of a fossil, informing us of the state of the galaxy at the time of its formation, underlining astronomers. With the help of the second catalog given in 2018, astronomers were able to show that our galaxy was “united” ten billion years ago.

The new catalog also offers a measure of unparalleled accuracy for 156,000 asteroids in our solar system, breaking the combination of 60,000 of them.

It will take five years to provide this third catalog of observations spread from 2014 to 2017. And it will have to wait until 2030 to get the final version, when Gaia will finish space scanning in 2025.

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