European Star Survey Reveals Celestial Treasure Trove

A sample of the Milky Way stars in Gaia’s data release 3 in a handout released on June 13, 2022. The color indicates the stellar metallicity. Redder stars are richer in metals. ESA Handout via AP

BERLIN—The European Space Agency released a trove of data Monday on almost 2 billion stars in the Milky Way, collected by its Gaia space observatory 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.

“This is an incredible gold mine for astronomy,” said Antonella Vallenari, who helped lead a consortium of 450 scientists and engineers who spent years turning the measurements collected by the space probe into usable data.

Gaia was also able to detect more than 100,000 starquakes, which the ESA likened to large tsunamis that ripple across stars. They appear to make the stars blink and allow scientists to deduce their density, interior rotation and inside temperature, astrophysicist Conny Aerts said.

Although it has only collected information on about 1 percent of the Milky Way’s stars, the Gaia 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.

This map shows 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 via AP

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.