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The European Space Agency’s (ESA) Gaia mission on Monday unveiled the third catalog of data from the Milky Way. This new crop includes details of nearly two billion stars in our galaxy.

Three-dimensional Milky Way mapping with unparalleled precision: This is the purpose of the Gaia Mission, launched by ESA in 2013, with the participation of about fifty institutions and research centers, including the University of Geneva. (UNIGE).

Located 1.5 million kilometers from Earth, opposite the Sun, the Gaia satellite collects valuable data from stars for its two-field-of-view telescope and its billion-pixel camera. These are processed by about 500 researchers, mainly based in Europe.

“The Gaia mission is unparalleled,” explained Mark Audard, a senior lecturer and researcher at UNIGE’s astronomy department, quoting a UNIGE press release on Monday: “About 2 billion sources have been identified – about 1% of the country’s total stars. And they’ve been monitored an average of 50 times each. It’s a real big data project. “

The Gaia Satellite lists and constantly observes stars sometimes thousands of light-years away, but they also include asteroids, extraterrestrial planets, and distant galaxies. Its introduction is the number of objects multiplied by 10,000 and the accuracy of the data by a factor of 100.

Index growth

Following the release of two catalogs, in 2016 and 2018, Gaia Mission today unveiled a new crop – Gaia Data Release 3 (DR3) – that takes us beyond the limits of our knowledge.

“Each new publication of Gaia Data allows for index growth in the source and type of data identified,” explained Laurent Eyre, a lecturer and researcher in the UNIGE astronomy department and coordinator of the consortium’s variability unit.

“Here, not only are the positions, distances and motions of the stars more detailed, we have published about ten million sources whose light intensity is variable, classified and studied in detail. In addition, we have been able to do for about 30 types. Stars or vibrating stars, for example – only 6 for ‘DR2’, experts add.

At its Ecogia site, Versoix, UNIGE significantly measured the variability of the light they emitted. A particularly useful element for determining their properties – their mass and their radius, for example – but also for calculating the distances of the universe.

To process this huge mass of data – 2 billion sources and about 400 billion optical measurements – the UNIGE team has used artificial intelligence, more specifically “machine learning”.

Available to scientists and the public

Gaia provides an opportunity to learn more about the chemical composition of stars, which makes it possible to get information about their place of birth and then their journey, hence the history of the Milky Way. The catalog published on Monday thus offers the largest chemical map of the galaxy.

This information is now available to the scientific community but also to the general public. Also, the consortium announced the publication of about 50 scientific articles based on “DR3” – the most signed by the UNIGE team as the first author or co-author – of which 17 came from variability analysis.

A special edition of the journal Astronomy & Astrophysics will be dedicated to it. Publications of the previous catalog produced a total of 6,000 articles. Papers dealing exclusively with Gaia data are the most cited in the field of astronomy. The satellite still needs to collect data by 2025.

This article has been published automatically. Source: ats

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