NASA's James Webb Space Telescope has resolved a significant astronomical mystery by confirming Hubble Space Telescope's findings about planet formation around ancient stars. This breakthrough enhances understanding of conditions under which planets may have formed in the early universe.
In 2003, Hubble observed a massive planet orbiting an ancient star, raising questions about planet formation in stars with minimal heavy elements. Conventional models suggested that such stars would have short-lived planet-forming disks, insufficient for substantial planet growth.
Researchers utilized Webb to study the Small Magellanic Cloud, focusing on NGC 346, a massive star-forming cluster where Hubble had previously detected stars aged 20 to 30 million years still surrounded by planet-forming disks. This contradicts the belief that these disks dissipate within 2 to 3 million years.
Guido De Marchi, study leader at the European Space Research and Technology Centre, emphasized Webb's role in confirming Hubble's findings. The new observations revealed that these older stars are still accumulating material from their surrounding disks, allowing more time for planets to form compared to those in the Milky Way.
The research team proposed two mechanisms for the longevity of these disks in low-metallicity environments. First, radiation pressure from stars may be less effective in dispersing disks with fewer heavy elements. Second, a larger initial gas cloud could lead to a more massive disk, prolonging its existence despite radiation pressures.
Elena Sabbi, chief scientist at the National Science Foundation's NOIRLab, noted that these findings significantly impact understanding of planet formation and system architecture in various cosmic environments. The team's findings were published in The Astrophysical Journal.