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How the planets evolved into the variety of worlds we see in our universe remains one of the most pressing questions for scientists, unraveling how we got here and where we are going.
Now a team of scientists has used data from the Webb Space Telescope to solve a mystery raised by the veteran space telescope 20 years ago, shaking up what planetary scientists know about how the earliest worlds formed from the cosmic ether.
In 2003, the Hubble Space Telescope discovered what appeared to be the oldest known planeta giant world that is about 13 billion years old. The discovery raised questions about how such worlds were born when their host stars were equally young and contained only small amounts of heavier elements — a crucial ingredient in planet formation as we know them.
In the new study, a team used the Webb Telescope, a state-of-the-art space observatory capable of observing the earliest detectable light, to study stars in a nearby galaxy that lack the same heavy elements. The team found that these stars have planet-forming disks that are older than the stars around the young stars in our galaxy.
“With Webb, we have a really strong confirmation of what we saw with Hubble, and we need to rethink how we model planet formation and early evolution in the young universe,” said Guido De Marchi, a researcher at the European Space Research and Technology Center. and lead author of the study at NASA release.
In a new study, has been published Earlier this month in The Astrophysical Journal, a team observed stars in NGC 346, a star-forming cluster in the Small Magellanic Cloud. The stars ranged in mass from about 0.9 times the mass of the Sun to 1.8 times the mass of the host star.
The team found that even the oldest stars they looked at were still accreting gas and that the stars had disks around them. This confirmed observations made by Hubble in the mid-2000s, which revealed stars tens of millions of years old and harboring planet-forming disks — disks that were generally thought to disintegrate after a few million years.
Overall, the team wrote in the paper, the findings “suggest that in low-metallicity environments, stellar circumstellar discs may survive longer than previously thought.”
The researchers believe that the discs can remain for several reasons. One possibility is that the lack of heavy elements actually benefits the discs, allowing them to better withstand the star’s radiation pressure, which would otherwise blow them away quickly. Another possibility is that Sun-like stars form from large clouds of gas that simply take longer to disintegrate because they are larger.
“With more matter around stars, accretion takes longer,” Elena Sabbi, senior scientist at the National Science Foundation’s Gemini Observatory, said in the same release. “The discs take ten times longer to disappear. This affects how you shape the planet and the type of system architecture you can have in these different environments. It’s very exciting.”
The team used the Webb Space Telescope’s Near-Infrared Spectrograph (NIRSpec) instrument to examine the stars peppered across the Small Magellanic Cloud. Last year, a group of scientists used NIRSpec to see silty clouds on a nearby exoplanet; earlier this year the tool was used to detect the first word Einstein Zig-Zag in space. Unlike spectrographs in older space observatories, Webb NIRSpec can observe 100 targets simultaneously, speed up data collection and discovery via proxy.
A look at both ancient and young star-forming regions could help shed light on the origins of our own solar system, which is about 4.6 billion years old.
