Scientists map the stars of the Milky Way using the European Space Telescope

A European space telescope has revealed vast details of the stellar diversity within our Milky Way, which will help scientists reconstruct the galaxy’s evolution and predict its evolution billions of years into the future.

Astronomers are using new data from the Gaia Observatory to map the motions and chemical signatures of nearly two billion stars — giants and dwarfs, big and small — including some violent vibrations during events known as “stellar earthquakes.”

The Multidimensional Cosmic Survey was released on Monday by the European Space Agency (ESA). Astronomers have compared its impact on their field to genetic analysis in biology.

“Our galaxy is a beautiful melting pot of stars,” said Alejandra Recio Blanco of the Observatoire de la Côte d’Azur and member of the Gaia cooperative. “This diversity is very important because it tells the story of the formation of our galaxy . . . It also clearly shows that we all belong to an ever-changing system, created thanks to an assembly of stars and gases of different origins.”

Gaia is located in a special orbit 1.5 million kilometers from Earth, called Lagrange point L2, near the new James Webb Telescope launched into space late last year. Gaia’s sample of 1.8 billion stars represents about one percent of the total number of stars in the Milky Way.

“Gaya is a survey mission,” said Timo Prosti, a project scientist at the European Space Agency, unlike many other observatories, such as the Webb and Hubble Space Telescopes. This approach, he said, means “that Gaia must make discoveries that other more specialized tasks will not miss.”

“We can’t wait for the astronomy community to dive into our new data to discover more about our galaxy and its surroundings,” Prostie said.

The data release adds new information about the stars’ chemical composition, temperature, mass, and speed of movement toward or away from the solar system. Many stars like the Sun contain heavy metals recycled from previous generations of stars that were born and died over the 13.6 billion year history of the Milky Way, although some contain only the primordial light elements, hydrogen and helium.

An unexpected discovery from the new data is Gaia’s ability to detect stellar earthquakes – strong oscillations, like stellar tidal waves, that have been detected in thousands of stars. “Starquakes teach us a lot about stars, especially their inner workings . . . in the same way that earthquakes help us understand what is going on inside our planet,” said Connie Aerts, a stellar seismologist at KU Leuven in Belgium.

Although Gaia launched in 2013 primarily to map stars, it also catalogs other objects, from the millions of galaxies outside the Milky Way to asteroids within our solar system.

The telescope began discovering planets orbiting the stars it surveys, known as exoplanets. About 200 potential planets have been identified elsewhere in the Milky Way so far, said Anthony Brown, president of the Gaia Data Analysis Consortium, “but it should be able to identify tens of thousands of exoplanets when we receive more data.”

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