The James Webb Space Telescope has found evidence that gas giants may have formed more easily in the early universe than previously thought. This challenges current theories on planet formation and evolution.
Astronomers have long believed that planets couldn’t form so early in the universe’s history because there wasn’t enough time for generations of stars to produce heavy elements needed for planetary growth. However, a 2003 discovery by the Hubble Space Telescope found a massive exoplanet, PSR B1620-26b, which orbits two dead stars and is believed to be one of the oldest known exoplanets.
The new study, led by Guido De Marchi, used the Near-Infrared Spectrometer instrument on JWST to observe a young star cluster in the Small Magellanic Cloud. The team found that many young stars in this cluster still possess planet-forming disks around them, which contradicts expectations that these disks would have disappeared long ago.
The discovery suggests that planet-forming disks can survive even when they contain relatively few heavy elements and last longer than previously thought. This challenges current models of planet formation and has implications for how we understand the early universe and the types of planetary systems that can form in different environments.
According to De Marchi, two possible explanations for why these disks can last so long are:
1. The lack of heavy elements makes it harder for starlight to blow away the disk.
2. The formation of the star itself becomes harder without a large amount of matter, resulting in larger disks that take longer to disappear.
The study’s findings were published on December 16 in The Astrophysical Journal and have significant implications for our understanding of planet formation and evolution in the early universe.
Source: https://www.space.com/the-universe/exoplanets/hubbles-impossible-planet-explained-gas-giants-may-have-formed-fast-in-early-universe