The James Webb Space Telescope has confirmed long-held suspicions about how ancient stars host massive planets, solving a 20-year-old mystery that puzzled scientists.
In the early 2000s, NASA’s Hubble Space Telescope observed an object 2.5 times as large as Jupiter, formed in the Milky Way 13 billion years ago. This was one of the oldest known planets ever discovered. However, Hubble’s findings sparked confusion because stars in the early universe should have primarily consisted of light elements like hydrogen and helium.
Scientists initially believed that these light-element stars’ disks of dust and gas would be blown away by radiation within a few million years, leaving no disk to form a planet. Instead, heavy elements needed to build long-lasting planetary disks arrived with later supernova explosions.
Now, the James Webb Space Telescope has observed modern-day proxies for ancient stars in the NGC 346 cluster, located in the Small Magellanic Cloud. The JWST’s data show that these old stars still have surrounding disks, contradicting initial assumptions.
Researchers found two possible explanations: (1) light-element stars don’t undergo radioactive decay, reducing their radiation output and allowing planetary disks to persist longer; or (2) ancient star formation occurs from massive clouds of dust and gas, leaving behind enormous disks that can last for millions of years.
These findings have significant implications for planetary formation and system architecture. By providing a new understanding of how planets form around old stars, the James Webb Space Telescope has opened doors to further research in this area.
Source: https://www.livescience.com/space/astronomy/james-webb-telescope-solves-20-year-old-hubble-conundrum-and-it-could-finally-explain-why-the-universes-oldest-planets-exist