Webb telescope reveals new facts about the formation of planets in the early Universe
Kyiv • UNN
The James Webb Space Telescope has obtained the first-ever spectra of stars forming in NGC 346. It was discovered that planet-forming disks exist longer than previously thought, even in environments with a low amount of heavy elements.
Previous theoretical conclusions about the formation of planets in the early days of the Universe may be refuted. The James Webb Space Telescope has received new data.
Transmits to UNN with reference to European Space Agency.
Details
New data from the NASA/ESA/CSA James Webb Space Telescope casts doubt on previous ideas about the formation of planets in the early universe and clarifies the conclusion made by the NASA/ESA Hubble Space Telescope more than 20 years ago.
In 2003, Hubble spotted a massive planet around a very old star, almost as old as the Universe. This meant that some planets formed when our Universe was very young. And such planets had time to form and grow large inside their young disks, to become even larger than Jupiter. It was believed that stars had only a small number of elements that are the building blocks of planets.
So how could such a planet have formed? It was a mystery.
Thanks to observations made with the James Webb Space Telescope, researchers have recently discovered that some stars actually have planet-forming disks, and importantly, these disks live even longer than those observed around young stars in our Milky Way galaxy.
According to Guido De Marchi of the European Space Research Center (Nordwijk, the Netherlands), with the Webb telescope, researchers have convincing confirmation of what scientists have previously seen with Hubble.
For reference
In the early Universe, stars were formed mostly from hydrogen and helium and very small amounts of heavier elements such as carbon and iron.
Modern theoretical models predict that with such a small number of heavy elements, disks around stars have a short lifespan.
“But Hubble did see one of these planets, so what if the models were wrong and the disks could live longer?” - says Webb co-researcher Elena Sabbi.
How was the idea of planet-forming disks proved
According to ESA, scientists have trained the James Webb Space Telescope on the Small Magellanic Cloud, a dwarf galaxy that is one of the closest neighbors of the Milky Way. In particular, they studied the massive star-forming cluster NGC 346, which is also poor in heavy elements. This cluster serves as a close proxy for studying the stellar environment as in the distant Universe.
Hubble's observations of NGC 346 since the mid-2000s have revealed many stars 20 to 30 million years old that appear to still have planet-forming disks around them. This contradicted the conventional wisdom that such disks dissipate after 2-3 million years.
“Hubble's findings were controversial, contradicting not only empirical data about our galaxy but also modern models,” the researchers note.
But now, thanks to the sensitivity and resolution of the Webb Telescope, scientists have the first-ever spectra of emerging stars like the Sun and their immediate neighborhood in a nearby galaxy.
“We can see that these stars are indeed surrounded by disks and are still in the process of absorbing material, even at a relatively high age of 20 or 30 million years. This also means that planets have more time to form and grow around these stars than in nearby star-forming regions in our own galaxy,” said Guido De Marchi.
The discovery refutes previous theoretical predictions that the star will blow away the disk very quickly when there are very few heavier elements in the gas.
The researchers explained that there may be two different mechanisms that allow planet-forming disks to persist in environments that are poor in heavy elements.
First, in order to deflate the disk, the light of the star puts pressure on the gas in the disk. This process is more efficient when the gas contains elements heavier than hydrogen and helium. The massive star cluster NGC 346 contains only about ten percent of the heavier elements that are present in the chemical composition of our Sun.
So maybe the stars in this cluster just need more time to disperse their disk.
the second possibility is that a sun-like Star must be created from a larger cloud of gas that has heavier elements. A larger gas cloud will create a larger disk. When the disk has more mass, it will take longer to deflate the disk.
Recall
According to researchers, the new generation of Starlink satellites from SpaceX creates stronger interference for radio telescopes than previous versions. Researchers from the Netherlands warn that this could hinder astronomical research.
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