A European space telescope has revealed many details about the stellar diversity of our Milky Way, which will help scientists reconstruct the evolution of the galaxy and predict its development billions of years from now.
Astronomers are using new data from the Gaia Observatory to map the movements and chemical signatures of nearly 2 billion stars – giant and dwarf, old and young – some of which vibrate violently in events known as ” star quakes”.
The multidimensional cosmic survey was released by the European Space Agency (ESA) on Monday. Astronomers have compared its impact on their field to genomic analysis in biology.
“Our galaxy is a beautiful melting pot of stars,” said Alejandra Recio-Blanco of the Côte d’Azur Observatory and member of the Gaia collaboration. “This diversity is extremely important because it tells us the story of how our galaxy formed. . . It also clearly shows that we all belong to an ever-changing system, formed through the assembly of stars and gases of different origins.
Gaia sits in a special orbit 1.5 miles from Earth, called the L2 Lagrange point, near the new James Webb Telescope that was launched into space late last year. Gaia’s sample of 1.8 billion stars represents about 1% of the Milky Way’s total stellar population.
“Gaia is a survey mission,” said ESA project scientist Timo Prusti, unlike many other observatories, such as the Webb and Hubble space telescopes. He said this approach means “Gaia is bound to make discoveries that other, more dedicated missions would miss.”
“We can’t wait for the astronomical community to immerse themselves in our new data to learn even more about our galaxy and its surroundings,” Prusti said.
The data release adds new information about the chemical composition, temperature, mass, and speed of motion of stars toward or away from the solar system. Many stars such as the sun contain recycled heavy metals from previous generations of stars that have been born and died over the Milky Way’s 13.6 billion year history, although some contain only the primordial light elements, hydrogen and helium.
An unexpected discovery emerging from the new data is Gaia’s ability to detect starquakes – strong oscillations, like stellar tsunamis, detected in thousands of stars. Conny Aerts, an asteroseismologist at KU Leuven in Belgium, said: “Starquakes tell us a lot about stars, including their inner workings. . . in the same way that earthquakes help us understand what is happening inside our planet.
Although Gaia was launched in 2013 primarily to map stars, it also catalogs other objects, from millions of galaxies far beyond the Milky Way to asteroids inside our solar system.
The telescope begins to detect planets orbiting the stars it monitors, called exoplanets. Anthony Brown, president of the Gaia data analysis consortium, said about 200 likely planets elsewhere in the Milky Way had been identified so far “but it should be able to identify tens of thousands of exoplanets at as we receive more data”.