James Webb telescope's observations show ice-covered pebbles delivering water to young planets

NASA's James Webb Space Telescope has observed an elaborate cosmic supply chain consisting of ice-covered pebbles which are apparently drifting inward from the outer Solar System, the latest study revealed. It is delivering water to still-forming planets closer to their stars, which was a long-proposed theory of planet formation. 

Scientists are still baffled as to the origin of Earth's water. There are several ideas, including the theory that our water came from comets and asteroids that collided with Earth. There are several hypotheses with detailed scientific analysis on how Earth got its water. 

However, the Webb telescope has made a significant contribution to planetary science with its findings linked to planet creation theory. 

The evidence so far was masked by thick veils of dust in immature solar systems. However, the latest observations by the Webb telescope are significant. 

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Ice-covered pebbles from outer solar systems convey water to planets that are still developing closer to their stars. The findings were published on Nov 8 in a new paper in the journal The Astrophysical Journal Letters. The paper is titled "JWST Reveals Excess Cool Water near the Snow Line in Compact Disks, Consistent with Pebble Drift".  

As quoted by Universe Today, Andrea Banzatti, who is an assistant professor of physics at Texas State University, San Marcos, Texas, is the lead author, said: "Webb finally revealed the connection between water vapour in the inner disk and the drift of icy pebbles from the outer disk. This finding opens up exciting prospects for studying rocky planet formation with Webb!" 

To carry out the study, Banzatti and his colleagues used Webb's MIRI (Mid-Infrared Instrument) to study four young, Sun-like stars only two or three million years old and surrounded by protoplanetary disks. 

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Two of them were compact discs ranging in size from 10 to 20 AU, and the other two were extended discs ranging in size from 100 to 150 AU. The expanded discs also contain significant radial gaps. 

According to the pebble drift theory, compact discs convey frozen pebbles more efficiently into the inner solar system, well within Neptune's orbit in our Solar System. Extended discs, on the other hand, are less efficient at it, according to the notion. 

The powerful Medium-Resolution Spectrometer (MRS) on the James Webb collaborates with MIRI. The MRS can distinguish between cool and warm water, which is essential for unravelling the convoluted picture in protoplanetary discs. The MRS statistics suggested that compact discs contain more cool water than extended discs. 

The authors of the study said that they interpret the cool water emission as ice sublimation and vapour diffusion near the snow line, suggesting that there is indeed a higher inward mass flux of icy pebbles in compact disks. 

"Observation of this process opens up multiple exciting prospects to study planet formation chemistry in inner disks with JWST," the article read.