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'Waterfall' from gas revealed baby planets, said the study



(CNN) – Astronomers see three points around a star that can indicate baby planets formed and grew there, according to a new study.

This is the first time astronomers using the ALMA radio telescope have seen 3D motion of gas in the disk around the star where the planet formed. The study was published Wednesday in the journal Nature.

The current understanding of planet formation follows a certain sequence. The stars are formed from collapsing clouds of gas and dust. Then, a protoplanetary disk of residual gas and dust surrounds the star. Planets are formed from this disk, using the remaining gas and dust that creates stars to gather solid material for the planet.

This can happen for several million years when planets grow from dust rain into round objects with solid nuclei.

This young star is known as HD 163296. On the surrounding disk, there are several rings and gaps. Using ALMA, astronomers see gas flowing into three gaps in the disk, where they expect baby planets to form.

Although these flowing gases have been predicted because they affect the atmosphere of baby planets, this is the first time they have been observed. This gas is the source of the atmosphere.

"We were surprised by how dynamic the disc was," said Jaehan Bae, study co-author and postdoctoral colleague Sagan at the Carnegie Institution for Science. "There are many things that happen around this star."

The gap lies in 87, 140 and 237 astronomical units of its host star. An astronomical unit is equal to the distance between the Earth and the sun.

"What is most likely to happen is that a planet in orbit around a star pushes gas and dust aside, opening a gap," said Richard Teague, author of a major study at the University of Michigan. "The gas above the gap then collapses into it like a waterfall, causing the gas flow to rotate in the disk."

To test ALMA observations, they created simulations of star systems and added three planets instead of gas. One planet has half the mass of Jupiter, the other is the same as Jupiter and the third planet is twice the mass of Jupiter.

Simulation according to what they see.

"Planets form in the middle layer of the disc, called the midplane," Teague said. "This is a cold place, protected from star radiation. We think that the gap caused by the planet carries warmer gas from the outer layer of the disk which is more chemically active, and that this gas will form the planet's atmosphere."

Being able to observe planets as they form will enable astronomers to understand more about their atmosphere. In the future, they hope to determine the chemical composition of the atmosphere.

Last year, several astronomers involved in this research helped create a new method for discovering exoplanets, or planets outside our solar system, by detecting this gas flow. By studying the gases in the protoplanetary disk, where carbon monoxide gas has the brightest signature, they can use ALMA to find these different wavelengths.

"With the high fidelity data from this program, we can measure gas speeds in three directions, not just one," Teague said. "For the first time, we measured the movement of gas that rotates around a star, towards or away from the star, and up or down the discs."

Another potential cause of gas flow is the star's magnetic field which creates gaps in the gas.

"At present, only direct observations of planets can rule out other choices," Bae said. "But this gas flow pattern is unique and very likely only due to the planet."

This story was first published on CNN.com "& # 39;Waterfalls from gas reveal baby planets, said the study"


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