New Delhi: The James Webb Space Telescope has turned its sensitive infrared gaze towards a star cluster on the fringes of a satellite galaxy of the Milky Way, the Small Magellanic cloud at a distance of about 200,000 lightyears from the Earth. The young star cluster is pristine, and similar to the first star clusters in a young universe, when the stars had not yet cooked up the heavier elements within the nuclear furnaces at their cores. The star cluster, designated as NGC 602 has very low abundances of elements heavier than hydrogen and helium, which were the first elements to form in the Big Bang.
The associated stellar nursery contains clouds of ionised atomic hydrogen. NGC 602 provides scientists with a valuable window into observing star formation in conditions that are very different from the local universe. An international team of scientists have discovered the first candidate brown dwarfs outside the Milky Way within NGC 602. Brown dwarfs are exotic objects that straddle the mass gap between the largest planets and the smallest stars. They are formed in a similar manner as stars, but do not accrete sufficient mass to sustain nuclear fusion, and are thus considered failed stars. The astronomers used the Hubble Space Telescope to observe the young star cluster as well.
Metal Poor Brown Dwarfs
The brown dwarf candidates are among the least metallic brown dwarfs spotted. A paper describing the findings has been published in The Astrophysical Journal. One of the authors of the study, Antonella Nota says, “This discovery highlights the power of using both Hubble and Webb to study young stellar clusters. Hubble showed that NGC602 harbors very young low mass stars, but only with Webb we can finally see the extent and the significance of the substellar mass formation in this cluster. Hubble and Webb are an amazingly powerful telescope duo!”
