Free Astronomy Magazine March-April 2025

MARCH-APRIL 2025 the process of gobbling material, even at the relatively old age of 20 or 30 million years,” said De Marchi. “This also implies that planets have more time to form and grow around these stars than in nearby star-form- ing regions in our own galaxy.” This finding refutes previous theo- retical predictions that when there are very few heavier elements in the gas around the disk, the star would very quickly blow away the disk. So the disk’s life would be very short, even less than a million years. But if a disk doesn’t stay around the star long enough for the dust grains to stick together and pebbles to form and become the core of a planet, how can planets form? The re- searchers explained that there could be two distinct mechanisms, or even a combination, for planet-forming disks to persist in environments scarce in heavier elements. First, to be able to blow away the disk, the star applies radiation pres- sure. For this pressure to be effec- T his side-by-side comparison shows a Hubble image of the massive star cluster NGC 346 (left) versus a Webb image of the same cluster (right). While the Hubble image shows more nebulosity, the Webb image pierces through those clouds to reveal more of the cluster’s structure. NGC 346 has a rela- tive lack of elements heavier than helium and hydro- gen, making it a good proxy for stellar environments in the early, distant universe. [NASA, ESA, CSA, STScI, Olivia C. Jones (UK ATC), Guido De Marchi (ESTEC), Margaret Meixner (USRA), Antonella Nota (ESA)]