A team of scientists has solved a mystery that has puzzled planetary experts for over two decades. Using data from the Webb Space Telescope, they confirmed what was initially observed by the Hubble Space Telescope in 2003 – the presence of ancient planetary disks around massive stars.
The discovery raises questions about how such worlds formed when their host stars were young and lacked heavy elements, a crucial ingredient for planet formation. The new research focused on stars in a nearby galaxy that are similarly lacking in heavy elements. These stars have planet-forming disks, which are older than those around young stars in our own galaxy.
According to Guido De Marchi, lead author of the study, “With Webb, we have a really strong confirmation of what we saw with Hubble, and we must rethink how we model planet formation and early evolution in the young universe.” The team observed stars in NGC 346, a star-forming cluster in the Small Magellanic Cloud, using the Webb telescope’s Near-Infrared Spectrograph.
Their findings indicate that even the oldest stars still accrete gas, with disks appearing around them. This challenges previous assumptions that these disks dissipate quickly after a few million years. The researchers believe that the lack of heavy elements may actually benefit the disks, allowing them to withstand radiation pressure and stick around for longer periods.
The implications are significant, as they suggest that circumstellar disks can live longer than previously thought in low-metallicity environments. This could have major implications for planet formation and system architecture. According to Elena Sabbi, “With more matter around the stars, the accretion lasts for a longer time… The disks take ten times longer to disappear.”
Source: https://gizmodo.com/webb-telescope-solves-a-20-year-old-planetary-mystery-sparked-by-hubble-2000542398