Astronomers have utilized ESO’s Visible and Infrared Survey Telescope for Astronomy (VISTA) to construct an extensive infrared atlas of five nearby stellar nurseries, using over one million images. These vast mosaics reveal young stars in the process of formation, concealed in thick clouds of dust. This novel tool enables astronomers to unravel the intricate enigma of stellar birth.
The team, headed by Stefan Meingast, an astronomer from the University of Vienna, Austria, published their findings in Astronomy & Astrophysics. They stated that “even the faintest sources of light, like stars far less massive than the sun, revealing objects that no one has ever seen before” could be detected in the images. The astronomer further added that the findings would allow scientists to understand the processes that transform gas and dust into stars.
The formation of stars occurs when clouds of gas and dust collapse under their gravity. The details of this process are not entirely understood. How many stars are born out of a cloud? What is their mass? How many of these stars will also host planets? To answer these questions, Meingast’s team utilized VISTA’s infrared camera VIRCAM to study five nearby star-forming regions at ESO’s Paranal Observatory in Chile. By capturing light originating from deep inside the clouds of dust, the team was able to use infrared wavelengths to study the concealed stars. As Alena Rottensteiner, a Ph.D. student and co-author of the study from the University of Vienna, explains, “The dust obscures these young stars from our view, making them virtually invisible to our eyes. Only at infrared wavelengths can we look deep into these clouds, studying the stars in the making.”
The VISIONS survey focused on observing star-forming regions within five constellations: Orion, Ophiuchus, Chamaeleon, Corona Australis, and Lupus. These regions are located less than 1,500 light-years away and are so vast that they span a significant area in the sky. VIRCAM’s field of view diameter, which is as wide as three full moons, makes it uniquely suited to map these massive regions.
Over five years, the team acquired more than one million images that were pieced together into large mosaics, unveiling vast cosmic landscapes. These panoramas display dark dust patches, luminous clouds, newly formed stars, and distant background stars from the Milky Way.
The VISIONS data allows astronomers to study the movement of young stars since the same areas were observed repeatedly. By monitoring these baby stars over several years, the team can measure their motion and learn how they depart from their parent clouds. João Alves, the Principal Investigator of VISIONS, explains that these measurements are challenging, with the apparent shift of these stars from Earth as small as the width of a human hair seen from 10 kilometers away. These measurements of stellar motions complement those obtained by the European Space Agency’s Gaia mission at visible wavelengths, where young stars are concealed by thick veils of dust.
The VISIONS atlas will keep astronomers occupied for years to come, providing long-lasting value for the astronomical community. Furthermore, VISIONS will set the groundwork for future observations with other telescopes, such as ESO’s Extremely Large Telescope (ELT), which is currently under construction in Chile and set to start operating later this decade. Meingast concludes that the ELT will allow astronomers to zoom into specific regions with unparalleled detail, providing a never-seen-before close-up view of individual stars in the process of formation.