This all-sky view provided by European Space Agency on Monday, June 13, 2022 shows a sample of the Milky Way stars in Gaia’s data release 3. The colour indicates the stellar metallicity. Redder stars are richer in metals. (ESA Handout via AP)

European ‘star survey’ reveals celestial treasure trove

The European Space Agency (ESA) has released a trove of data on almost two billion stars in the Milky Way, collected by its Gaia mission in an effort to create the most accurate and complete map of our galaxy.

Astronomers hope to use the data to understand better how stars are born and die, and how the Milky Way evolved over billions of years.

The new data includes new information such as the age, mass, temperature and chemical composition of stars.

This can be used, for example, to determine which stars were born in another galaxy and then migrated to the Milky Way.

Gaia was also able to detect more than 100,000 so-called starquakes, which ESA likened to large tsunamis that ripple across stars.

The interstellar dust that fills the Milky Way. The dark regions in the centre of the Galactic plane in black are the regions with a lot of interstellar dust fading to the yellow as the amount of dust decreases. The dark blue regions above and below the Galactic plane are regions where there is little dust
The interstellar dust that fills the Milky Way. The dark regions in the centre of the Galactic plane in black are the regions with a lot of interstellar dust fading to the yellow as the amount of dust decreases. The dark blue regions above and below the Galactic plane are regions where there is little dust (ESA Handout/AP)

These allow scientists to deduce the density, interior rotation and temperature inside stars, astrophysicist Conny Aerts said.

Although it has only collected information on about 1% of the Milky Way’s stars, the mission is already providing the basis for around 1,600 scientific publications a year.

Project scientist Timo Prusti said the sheer number of stars observed makes it more likely that scientists will make very rare discoveries.

“You have to observe a lot of objects in order to get the needle in the haystack,” he said.

ESA chief Josef Aschbacher said having more data also allows astronomers to understand some of the forces at play in the galaxy, such as the way our own solar system is being thrown about inside the Milky Way.

“It is enabling things that would never be possible without this large number of data,” he said.

The Gaia data now being released also includes information on 800,000 binaries — stars that move in tandem with each other — as well as several new exoplanets, hundreds of thousands of asteroids in the solar system and millions of objects beyond our galaxy.

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