Euclid’s new picture reveals more than 60 million stars and provides new insights into exoplanet detection through microlensing, giving astronomers a powerful tool to study the hidden worlds of our galaxy.
(CN) – The European Space Agency released the largest and most detailed picture ever taken of the center of our galaxy on Wednesday.
The picture, which includes more than 60 million stars, nebulae and star clusters, was taken by the European Space Agency’s Euclid space telescope on March 23, 2025, over 26 hours.
The telescope, which became operational in 2023, is designed to observe billions of galaxies through its visible-light camera, which allows it to spot individual stars in extremely bright and crowded areas such as the galactic center, also known as galactic bulge.
This ability to identify individual stars in extremely bright environments makes the telescope perfect for taking a picture of the center of the galaxy so astronomers can study the stars and planets that inhabit their orbits, the European Space Agency said. in a press release.
This crowded region of the galaxy is the perfect place for astronomers to search for new planets through the technique of microlensinga technique used by astronomers to gather data about various planets and their possible habitability. But the technique requires an observation point and more than a star.
“To capture the microlens, you need to observe parts of the sky that are full of stars, such as near the center of our galaxy,” said Jean-Philippe Beaulieu of the Institut d’Astrophysique de Paris and the University of Tasmania in Australia. the notice says. “Over the past 20 years, almost 300 exoplanets have been discovered using this technique, all with ground-based telescopes and all towards the center of our galaxy. This image from Euclid includes 51 known planetary systems – and will help study many more to be found.”
Basically, the telescope observes two stars as a closer star passes in front of a more distant star. But because space-time bends around these massive objects, light from the most distant star is bent as it travels through the warped space-time around the nearest star. The reaction produces a natural zoom effect from the most distant star. But even planets can produce the effect on a much smaller scale.
Although Euclid’s 26-hour observation is not long enough to detect a microlensing event, its latest image allows scientists to measure the mass of planets that are already known, as well as planets that have yet to be discovered.
The picture is described as a mosaic of nine “dots” targeting different sections of the galactic center. This mosaic includes the entire region that NASA’s upcoming Rome Space Telescope will monitor for microlensing events when it comes online in August.
“This means that anyone who detects a microlensing event in the same region, for example with Roman, will from now on be able to use the Euclid data as a time reference in the past and see what the stars looked like before they overlapped,” said Natalia Rektsini, also from the Institut d’Astrophysique de Paris, who led the release of the Euclid Science Center data to the galactic community. “Since Euclid can clearly separate individual stars, he can then measure how fast they move over time and use that information to confirm the existence of a planet and determine its mass. This would not be possible with point-in-time data.”
Although most planet-hunting techniques rely on detecting hot planets orbiting massive STARSmicrolensing allows astronomers to detect whatever is out there.
“This technique is unbiased, we detect whatever is there,” said Rektsini. “It is uniquely suited to detect cool exoplanets. And we expect every star in the Milky Way to host at least one such planet.”
Among Euclid’s data so far are two colder stars exoplanets. Beaulieu led the discovery of one of the planets 20 years ago, he said.
“It’s an icy planet, a bit like Hoth from Star Wars,” he said. “After all this time, I’m thrilled that Euclid can finally let us measure his exact mass.”
The other planet belongs to a fascinating system, Rektsini said.
“It consists of two stars and a planet,” she added. “By combining previous observations from Keck and Hubble with the new Euclid data, we can finally separate the stars and confirm the mass of the planet.”
The results show what a small, dedicated team can achieve on a large international mission, said Euclid project scientist Valeria Pettorino.
“In just 24 hours, Euclid has provided unique data on the center of the Milky Way, with a large and clear view of this region,” she said. “Over time, the separation between sources and lenses increases. This is why these Euclid data will be a temporal reference for past and future missions and enable studies of exoplanets and their masses. These data can also be used for other scientific applications, from brown dwarfs and binary stars to stellar motions and dust throughout our galaxy.”
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