Astronomers have unveiled an extraordinary image of the Milky Way's heart, captured by the European Space Agency's (ESA) Euclid telescope. The dazzling mosaic depicts more than 60 million individual stars within the galactic bulge, representing the largest and most detailed visible light shot ever taken of our galaxy's crowded centre.
Launched in 2023 with a mission to create the most accurate 3D map of the cosmos and investigate dark matter and dark energy, the Euclid telescope has proven unexpectedly adept at exoplanet detection. Its sensitive visible light camera is uniquely capable of separating individual stars in the densely packed central region of the Milky Way, offering an unparalleled view.
Dr Eamonn Kerins, an astrophysicist at the University of Manchester’s Jodrell Bank Centre for Astrophysics, highlighted the significance of this achievement. He stated that while Euclid was not specifically designed for this purpose, its capabilities have exceeded expectations, effectively 'firing the starting pistol' on a new era of exoplanet discovery. The research anticipates a dramatic increase in known exoplanets, potentially soaring from the current count of approximately 6,000 to over 100,000 across the galaxy.
The image, which comprises a mosaic of nine distinct 'pointings' taken over 26 hours of observation in March last year, is more than just a visually stunning spectacle. It provides crucial baseline data for identifying exoplanets through a technique known as microlensing. This method involves observing a distant star's light being bent and brightened by the gravity of a closer foreground star. The presence of a planet orbiting the nearer star can cause a distinctive spike in this brightening effect.
This new data from Euclid will significantly enhance future exoplanet missions, including NASA's Nancy Grace Roman Space Telescope, which is scheduled for launch in August. While Roman is expected to identify around 1,500 microlensing exoplanets, the Euclid image, by showing the same stars before they overlap, allows astronomers to precisely measure their movement and confirm planetary existence and mass. Dr Kerins noted that the Euclid snapshot could improve these measurements by up to a factor of three, a remarkable achievement for a single image. Furthermore, Euclid's data will help differentiate genuine transiting planets from other celestial phenomena, such as binary star systems, which can produce similar signals. The findings from this research are expected to be peer-reviewed.
Source: European Space Agency (ESA), University of Manchester