France Press Agency, Published on Saturday, June 11, 2022 at 10:30 p.m.
The Gaia mission, whose space telescope detailed the Milky Way, unveiled an informative new version on Monday of nearly two billion stars who have tracked their paths and analyzed properties.
“This is the Swiss Army knife of astrophysics. “There is not a single astronomer who does not use his data directly or indirectly,” the Côte d’Ivoire astronomer told AFP. France.
The Astronomy Community will be able to draw from Monday, from 10:00 GMT, on the third catalog of data collected by the instrument. Harvest, accompanied by about fifty scientific articles, lists a number of celestial bodies.
From the closest, with more than 150,000 asteroids in our solar system, “for which the instrument has calculated their orbit with incomparable accuracy,” says Mr. Maynard, to new measurements involving more than 1.8 billion stars from the Milky Way. road. And beyond this galaxy: groups of other galaxies and distant quasars.
Launched on behalf of the European Space Agency (ESA), Gaia has been operating since 2013 and is located in a privileged place called L2, one and a half million kilometers from Earth, facing the Sun.
– clear the sky –
“Gaia scans the sky and captures everything she sees,” said astronomer Misha Haywood of the Paris-PSL Observatory. It detects and observes a very small fraction (only 1%) of the stars in our galaxy that are 100,000 light-years in diameter.
But he draws more than just a map. Its two telescopes are connected to a billion-pixel photographic sensor, with commercial cameras numbering in the millions. Three astronomical instruments, photometry and spectroscopy, will interpret and subsequently extract real photons and light signals.
“Thanks to this, it provides global monitoring of the positions of what is moving in the sky. This is the first time, “Mr Haywood continued. Before Gaia, “We had very limited views of the galaxy.”
before Gaia? Hipparcos, the satellite that revolutionized surveillance since its launch by the European Space Agency in 1997, cataloging more than 110,000 celestial bodies.
With Gaia, astronomers have access not only to the positions and movements of a large number of stars, but also to measurements of their physical and chemical characteristics, and their age is just as important.
Astronomer Paula Di Mateo, a colleague of Misha Haywood of the Paris-PSL Observatory, explains much of the information, “which tells us about their past evolution and thus about the evolution of the galaxy.”
– great discoveries –
This is also “one of the reasons Gaia was built,” the astronomer continued. “Stars have the peculiarity of life for billions of years. So measuring them is like measuring fossils that tell us about the state of the galaxy during its formation.
This review of the movement of the stars of the Milky Way has already led to great discoveries. With the second catalog, delivered in 2018, astronomers were able to show that our galaxy “merged” with ours ten billion years ago.
The catalog has produced thousands of scientific papers since its first edition in 2016. Francois explains that the data flow requires a special terrestrial processing circuit, DPAC, which calls supercomputers for six European data centers, mobilizing 450 specialists. Maynard, who was responsible.
“Without this processing package, there is no task,” because Gaia produces 700 million stellar objects, 150 million photometers and 14 million spectra every day. A stream of raw data that human-led algorithms convert into measurements that astronomers can use.
The delivery of this third catalog of observations will take five years from 2014 to 2017. And it will be necessary to wait until 2030 for the final version, when Gaia will complete the scan of space in 2025.
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